๐Ÿ“ Grade 10 Maths ยท Unit 5 ยท Samacheer Kalvi

Samacheer Class 10 Maths - Coordinate Geometry

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Complete step-by-step solutions for every exercise in Unit 5. Click any question to expand the full working.

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๐Ÿ“‹ Exercises in this unit
Ex 5.1 โ€” Area of a Triangle and Quadrilateral Ex 5.1 โ€” -- Ex 5.2 โ€” Inclination of a Line Ex 5.2 โ€” -- Ex 5.3 โ€” Straight Line Ex 5.3 โ€” -- Ex 5.4 โ€” General Form of a Straight Line Ex 5.4 โ€” -- Ex 5.UE โ€” Unit Exercise
Your Progress โ€” Unit 5: Coordinate Geometry 0% complete
Ex 5.1Area of a Triangle and Quadrilateral1 questions
Q.1 Question 1 โ–พ
โœ“ Solution

Maths Book back answers and solution for Exercise questions - Mathematics : Coordinate Geometry: Area of a Triangle and Area of a Quadrilateral: Exercise Problem Questions with Answer

---


Ex 5.1--22 questions
Q.1 Find the area of the triangle formed by the points โ–พ
โœ“ Solution
(i) $$

(1,-1),\ (-4,6),\ (-3,-5) $$

(ii) $$

(-10,-4),\ (-8,-1),\ (-3,-5) $$

---

Q.2 Determine whether the sets of points are collinear? โ–พ
โœ“ Solution
(i) $$

\left(-\frac12,3\right),\ (-5,6),\ (-8,8) $$

(ii) $$

(a,b+c),\ (b,c+a),\ (c,a+b) $$

---

Q.3 Vertices of given triangles are taken in order and their areas are provided aside. In each case, find the value of $p$ โ–พ
โœ“ Solution

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Q.4 In each of the following, find the value of โ€˜aโ€™ for which the given points are collinear. โ–พ
โœ“ Solution
(i) $$

(2,3),\ (4,a),\ (6,-3) $$

(ii) $$

(a,2-2a),\ (-a+1,2a),\ (-4-a,6-2a) $$

---

Q.5 Find the area of the quadrilateral whose vertices are at โ–พ
โœ“ Solution
(i) $$

(-9,-2),\ (-8,-4),\ (2,2),\ (1,-3) $$

(ii) $$

(-9,0),\ (-8,6),\ (-1,-2),\ (-6,-3) $$

---

Q.6 Find the value of $k$, if the area of a quadrilateral is $28$ sq.units, whose vertices are โ–พ
โœ“ Solution

$$ (-4,-2),\ (-3,k),\ (3,-2),\ (2,3) $$

---

Q.7 If the points โ–พ
โœ“ Solution

$$ A(-3,9),\ B(a,b),\ C(4,-5) $$

are collinear and if

$$ a+b=1 $$

then find $a$ and $b$.

---

Q.8 Let โ–พ
โœ“ Solution

$$ P(11,7),\ Q(13.5,4),\ R(9.5,4) $$

be the mid-points of the sides $AB, BC, AC$ respectively of $\triangle ABC$.

Find the coordinates of the vertices $A,B,C$.

Hence find the area of $\triangle ABC$ and compare this with area of $\triangle PQR$.

---

Q.9 In the figure, the quadrilateral swimming pool shown is surrounded by concrete patio. Find the area of the patio. โ–พ
โœ“ Solution

---

Q.10 A triangular shaped glass with vertices at โ–พ
โœ“ Solution

$$ A(-5,-4),\ B(1,6),\ C(7,-4) $$

has to be painted.

If one bucket of paint covers $6$ square feet, how many buckets of paint will be required to paint the whole glass, if only one coat of paint is applied.

---

Q.11 In the figure, find the area of โ–พ
โœ“ Solution
(i) triangle $AGF$
(ii) triangle $FED$
(iii) quadrilateral $BCEG$

---

# Answers

Q.1 ### (i) โ–พ
โœ“ Solution

$$ 24 \text{ sq.units} $$

(ii) $$

11.5 \text{ sq.units} $$

---

Q.2 ### (i) โ–พ
โœ“ Solution

Collinear

(ii) Collinear

---

Q.3 ### (i) โ–พ
โœ“ Solution

$$ 44 $$

(ii) $$

13 $$

---

Q.4 ### (i) โ–พ
โœ“ Solution

$$ a=0 $$

(ii) $$

a=\frac12 \text{ or } -1 $$

---

Q.5 ### (i) โ–พ
โœ“ Solution

$$ 35 \text{ sq.units} $$

(ii) $$

34 \text{ sq.units} $$

---

Q.6 $$ โ–พ
โœ“ Solution

k=-5 $$

---

Q.7 $$ โ–พ
โœ“ Solution

a=2,\quad b=-1 $$

---

Q.8 $$ โ–พ
โœ“ Solution

\text{Area}(\triangle ABC)=24 \text{ sq.units} $$

$$ \text{Area}(\triangle ABC)=4\times \text{Area}(\triangle PQR) $$

---

Q.9 $$ โ–พ
โœ“ Solution

38 \text{ sq.units} $$

---

Q.10 $$ โ–พ
โœ“ Solution

10 \text{ cans} $$

---

Q.11 ### (i) โ–พ
โœ“ Solution

$$ 3.75 \text{ sq.units} $$

(ii) $$

3 \text{ sq.units} $$

(iii) $$

13.88 \text{ sq.units} $$

# UNIT 5 : Coordinate Geometry


Ex 5.2Inclination of a Line1 questions
Q.1 Question 1 โ–พ
โœ“ Solution

Maths Book back answers and solution for Exercise questions - Mathematics : Coordinate Geometry: Inclination of a line: Exercise Problem Questions with Answer

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Ex 5.2--28 questions
Q.1 What is the slope of a line whose inclination with positive direction of x-axis is โ–พ
โœ“ Solution
(i) $$

90^\circ $$

(ii) $$

0^\circ $$

---

Q.2 What is the inclination of a line whose slope is โ–พ
โœ“ Solution
(i) $$

0 $$

(ii) $$

1 $$

---

Q.3 Find the slope of a line joining the points โ–พ
โœ“ Solution
(i) $$

(5,\sqrt5) $$

with the origin.

(ii) $$

(\sin\theta,-\cos\theta) $$

and

$$ (-\sin\theta,\cos\theta) $$

---

Q.4 What is the slope of a line perpendicular to the line joining $A(5,1)$ and $P$ where $P$ is the midpoint of the segment joining โ–พ
โœ“ Solution

$$ (4,2)\text{ and }(-6,4) $$

---

Q.5 Show that the given points are collinear: โ–พ
โœ“ Solution

$$ (-3,-4),\ (7,2),\ (12,5) $$

---

Q.6 If the three points โ–พ
โœ“ Solution

$$ (3,-1),\ (a,3),\ (1,-3) $$

are collinear, find the value of $a$.

---

Q.7 The line through the points โ–พ
โœ“ Solution

$$ (-2,a)\text{ and }(9,3) $$

has slope

$$ -\frac12 $$

Find the value of $a$.

---

Q.8 The line through the points โ–พ
โœ“ Solution

$$ (-2,6)\text{ and }(4,8) $$

is perpendicular to the line through the points

$$ (8,12)\text{ and }(x,24) $$

Find the value of $x$.

---

Q.9 Show that the given points form a right angled triangle and check whether they satisfy Pythagoras theorem. โ–พ
โœ“ Solution
(i) $$

A(1,-4),\ B(2,-3),\ C(4,-7) $$

(ii) $$

L(0,5),\ M(9,12),\ N(3,14) $$

---

Q.10 Show that the given points form a parallelogram: โ–พ
โœ“ Solution

$$ A(2.5,3.5),\ B(10,-4),\ C(2.5,-2.5),\ D(-5,5) $$

---

Q.11 If the points โ–พ
โœ“ Solution

$$ A(2,2),\ B(-2,-3),\ C(1,-3)\text{ and }D(x,y) $$

form a parallelogram then find the values of $x$ and $y$.

---

Q.12 Let โ–พ
โœ“ Solution

$$ A(3,-4),\ B(9,-4),\ C(5,-7),\ D(7,-7) $$

Show that $ABCD$ is a trapezium.

---

Q.13 A quadrilateral has vertices at โ–พ
โœ“ Solution

$$ A(-4,-2),\ B(5,-1),\ C(6,5),\ D(-7,6) $$

Show that the midpoints of its sides form a parallelogram.

---

Q.14 $PQRS$ is a rhombus. Its diagonals $PR$ and $QS$ intersect at the point $M$ and satisfy โ–พ
โœ“ Solution

$$ QS=2PR $$

If the coordinates of $S$ and $M$ are

$$ (1,1)\text{ and }(2,-1) $$

respectively, find the coordinates of $P$.

---

# Answers

Q.1 ### (i) โ–พ
โœ“ Solution

$$ \text{Undefined} $$

(ii) $$

0 $$

---

Q.2 ### (i) โ–พ
โœ“ Solution

$$ 0^\circ $$

(ii) $$

45^\circ $$

---

Q.3 ### (i) โ–พ
โœ“ Solution

$$ \frac1{\sqrt5} $$

(ii) $$

-\cot\theta $$

---

Q.4 $$ โ–พ
โœ“ Solution

3 $$

---

Q.5 The points are collinear. โ–พ
โœ“ Solution

---

Q.6 $$ โ–พ
โœ“ Solution

a=7 $$

---

Q.7 $$ โ–พ
โœ“ Solution

a=\frac{17}{2} $$

---

Q.8 $$ โ–พ
โœ“ Solution

x=4 $$

---

Q.9 ### (i) โ–พ
โœ“ Solution

Yes

(ii) Yes

---

Q.10 The given points form a parallelogram. โ–พ
โœ“ Solution

---

Q.11 $$ โ–พ
โœ“ Solution

x=5,\quad y=2 $$

---

Q.12 $ABCD$ is a trapezium. โ–พ
โœ“ Solution

---

Q.13 The midpoints form a parallelogram. โ–พ
โœ“ Solution

---

Q.14 $$ โ–พ
โœ“ Solution

\left(1,-\frac32\right) $$

or

$$ \left(3,-\frac12\right) $$

# UNIT 5 : Coordinate Geometry


Ex 5.3Straight Line1 questions
Q.1 Question 1 โ–พ
โœ“ Solution

Maths Book back answers and solution for Exercise questions - Mathematics : Coordinate Geometry: Straight line: Exercise Problem Questions with Answer

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Ex 5.3--28 questions
Q.1 Find the equation of a straight line passing through the midpoint of a line segment joining the points โ–พ
โœ“ Solution

$$ (1,-5),\ (4,2) $$

and parallel to

(i) X-axis
(ii) Y-axis

---

Q.2 The equation of a straight line is โ–พ
โœ“ Solution

$$ 2(x-y)+5=0 $$

Find its

- slope - inclination - intercept on the $Y$-axis.

---

Q.3 Find the equation of a line whose inclination is $30^\circ$ and making an intercept $-3$ on the $Y$-axis. โ–พ
โœ“ Solution

---

Q.4 Find the slope and y-intercept of โ–พ
โœ“ Solution

$$ \sqrt3x+(1-\sqrt3)y=3 $$

---

Q.5 Find the value of $a$, if the line through โ–พ
โœ“ Solution

$$ (-2,3)\text{ and }(8,5) $$

is perpendicular to

$$ y=ax+2 $$

---

Q.6 The hill in the form of a right triangle has its foot at โ–พ
โœ“ Solution

$$ (19,3) $$

The inclination of the hill to the ground is $45^\circ$.

Find the equation of the hill joining the foot and top.

---

Q.7 Find the equation of a line through the given pair of points. โ–พ
โœ“ Solution
(i) $$

\left(2,\frac23\right)\text{ and }\left(-\frac12,-2\right) $$

(ii) $$

(2,3)\text{ and }(-7,-1) $$

---

Q.8 A cat is located at the point โ–พ
โœ“ Solution

$$ (-6,-4) $$

in the xy-plane.

A bottle of milk is kept at

$$ (5,11) $$

The cat wishes to consume the milk travelling through the shortest possible distance.

Find the equation of the path it needs to take.

---

Q.9 Find the equation of the median and altitude of $\triangle ABC$ through $A$ where the vertices are โ–พ
โœ“ Solution

$$ A(6,2),\ B(-5,-1),\ C(1,9) $$

---

Q.10 Find the equation of a straight line which has slope โ–พ
โœ“ Solution

$$ -\frac54 $$

and passing through the point

$$ (-1,2) $$

---

Q.11 You are downloading a song. โ–พ
โœ“ Solution

The percent $y$ (in decimal form) of megabytes remaining to get downloaded in $x$ seconds is given by

$$ y=-0.1x+1 $$

(i) Graph the equation.
(ii) Find the total MB of the song.
(iii) After how many seconds will $75\%$ of the song get downloaded?
(iv) After how many seconds will the song be downloaded completely?

---

Q.12 Find the equation of a line whose intercepts on the x and y axes are given below. โ–พ
โœ“ Solution
(i) $$

4,\ -6 $$

(ii) $$

-5,\ \frac34 $$

---

Q.13 Find the intercepts made by the following lines on the coordinate axes. โ–พ
โœ“ Solution
(i) $$

3x-2y-6=0 $$

(ii) $$

4x+3y+12=0 $$

---

Q.14 Find the equation of a straight line โ–พ
โœ“ Solution
(i) passing through

$$ (1,-4) $$

and has intercepts which are in the ratio $2:5$.

(ii) passing through

$$ (-8,4) $$

and making equal intercepts on the coordinate axes.

---

# Answers

Q.1 Midpoint of โ–พ
โœ“ Solution

$$ (1,-5)\text{ and }(4,2) $$

is

$$ \left(\frac52,-\frac32\right) $$

(i) Parallel to X-axis:

$$ y=-\frac32 $$

(ii) Parallel to Y-axis:

$$ x=\frac52 $$

---

Q.2 Given: โ–พ
โœ“ Solution

$$ 2(x-y)+5=0 $$

$$ 2x-2y+5=0 $$

$$ y=x+\frac52 $$

### Slope

$$ m=1 $$

### Inclination

$$ 45^\circ $$

### Y-intercept

$$ \frac52 $$

---

Q.3 $$ โ–พ
โœ“ Solution

m=\tan30^\circ=\frac1{\sqrt3} $$

Intercept on y-axis:

$$ c=-3 $$

Equation:

$$ y=\frac1{\sqrt3}x-3 $$

---

Q.4 Given: โ–พ
โœ“ Solution

$$ \sqrt3x+(1-\sqrt3)y=3 $$

$$ y=-\frac{\sqrt3}{1-\sqrt3}x+\frac3{1-\sqrt3} $$

### Slope

$$ m=-\frac{\sqrt3}{1-\sqrt3} $$

### Y-intercept

$$ \frac3{1-\sqrt3} $$

---

Q.5 Slope through the points: โ–พ
โœ“ Solution

$$ m=\frac{5-3}{8-(-2)} $$

$$ =\frac2{10}=\frac15 $$

Perpendicular slope:

$$ a=-5 $$

---

Q.6 Inclination: โ–พ
โœ“ Solution

$$ 45^\circ $$

So slope:

$$ m=1 $$

Passing through

$$ (19,3) $$

Equation:

$$ y-3=x-19 $$

$$ y=x-16 $$

---

Q.7 ### (i) โ–พ
โœ“ Solution

Equation:

$$ 8x-5y-12=0 $$

(ii) Equation:

$$ 4x-9y+19=0 $$

---

Q.8 Slope: โ–พ
โœ“ Solution

$$ m=\frac{11-(-4)}{5-(-6)} $$

$$ =\frac{15}{11} $$

Equation:

$$ y+4=\frac{15}{11}(x+6) $$

$$ 15x-11y+46=0 $$

---

Q.9 ### Median through A โ–พ
โœ“ Solution

Midpoint of $BC$:

$$ \left(-2,4\right) $$

Equation:

$$ x+4y-14=0 $$

### Altitude through A

Slope of $BC$:

$$ \frac{9-(-1)}{1-(-5)}=\frac{10}{6}=\frac53 $$

Perpendicular slope:

$$ -\frac35 $$

Equation:

$$ 3x+5y-28=0 $$

---

Q.10 Equation: โ–พ
โœ“ Solution

$$ y-2=-\frac54(x+1) $$

$$ 5y-10=-5x-5 $$

$$ 5x+5y-5=0 $$

or

$$ x+y-1=0 $$

---

Q.11 ### (ii) โ–พ
โœ“ Solution

Total MB of song:

$$ 1 $$

(iii) For $75\%$ downloaded,

$$ 25\%\text{ remaining}=0.25 $$

$$ 0.25=-0.1x+1 $$

$$ x=7.5 $$

seconds.

(iv) Downloaded completely:

$$ y=0 $$

$$ 0=-0.1x+1 $$

$$ x=10 $$

seconds.

---

Q.12 ### (i) โ–พ
โœ“ Solution

Intercept form:

$$ \frac{x}{4}+\frac{y}{-6}=1 $$

$$ 3x-2y=12 $$

(ii) $$

\frac{x}{-5}+\frac{y}{3/4}=1 $$

$$ -3x+20y=15 $$

---

Q.13 ### (i) โ–พ
โœ“ Solution

$$ 3x-2y-6=0 $$

x-intercept:

$$ 2 $$

y-intercept:

$$ -3 $$

(ii) $$

4x+3y+12=0 $$

x-intercept:

$$ -3 $$

y-intercept:

$$ -4 $$

---

Q.14 ### (i) โ–พ
โœ“ Solution

Equation:

$$ 5x+2y+3=0 $$

(ii) Equal intercepts:

$$ \frac{x}{a}+\frac{y}{a}=1 $$

$$ x+y=a $$

Passing through

$$ (-8,4) $$

$$ -8+4=a $$

$$ a=-4 $$

Equation:

$$ x+y+4=0 $$

# UNIT 5 : Coordinate Geometry


Ex 5.4General Form of a Straight Line1 questions
Q.1 Question 1 โ–พ
โœ“ Solution

Maths Book back answers and solution for Exercise questions - Mathematics : Coordinate Geometry: General Form of a Straight Line: Exercise Problem Questions with Answer

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Ex 5.4--39 questions
Q.1 Find the slope of the following straight lines โ–พ
โœ“ Solution
(i) $$

5y-3=0 $$

(ii) $$

7x-\frac{3}{17}=0 $$

---

Q.2 Find the slope of the line which is โ–พ
โœ“ Solution
(i) parallel to

$$ y=0.7x-11 $$

(ii) perpendicular to the line

$$ x=-11 $$

---

Q.3 Check whether the given lines are parallel or perpendicular. โ–พ
โœ“ Solution
(i) $$

\frac{x}{3}+\frac{y}{4}+\frac17=0 $$

and

$$ \frac{2x}{3}+\frac{y}{2}+\frac1{10}=0 $$

(ii) $$

5x+23y+14=0 $$

and

$$ 23x-5y+9=0 $$

---

Q.4 If the straight lines โ–พ
โœ“ Solution

$$ 12y=-(p+3)x+12 $$

and

$$ 12x-7y=16 $$

are perpendicular then find $p$.

---

Q.5 Find the equation of a straight line passing through the point โ–พ
โœ“ Solution

$$ P(-5,2) $$

and parallel to the line joining the points

$$ Q(3,-2)\text{ and }R(-5,4) $$

---

Q.6 Find the equation of a line passing through โ–พ
โœ“ Solution

$$ (6,-2) $$

and perpendicular to the line joining the points

$$ (6,7)\text{ and }(2,-3) $$

---

Q.7 $A(-3,0)$, $B(10,-2)$ and $C(12,3)$ are the vertices of $\triangle ABC$. โ–พ
โœ“ Solution

Find the equation of the altitude through $A$ and $B$.

---

Q.8 Find the equation of the perpendicular bisector of the line joining the points โ–พ
โœ“ Solution

$$ A(-4,2)\text{ and }B(6,-4) $$

---

Q.9 Find the equation of a straight line through the intersection of lines โ–พ
โœ“ Solution

$$ 7x+3y=10 $$

$$ 5x-4y=1 $$

and parallel to the line

$$ 13x+5y+12=0 $$

---

Q.10 Find the equation of a straight line through the intersection of lines โ–พ
โœ“ Solution

$$ 5x-6y=2 $$

$$ 3x+2y=10 $$

and perpendicular to the line

$$ 4x-7y+13=0 $$

---

Q.11 Find the equation of a straight line joining the point of intersection of โ–พ
โœ“ Solution

$$ 3x+y+2=0 $$

and

$$ x-2y-4=0 $$

to the point of intersection of

$$ 7x-3y=-12 $$

and

$$ 2y=x+3 $$

---

Q.12 Find the equation of a straight line through the point of intersection of the lines โ–พ
โœ“ Solution

$$ 8x+3y=18 $$

$$ 4x+5y=9 $$

and bisecting the line segment joining the points

$$ (5,-4)\text{ and }(-7,6) $$

---

# Answers

Q.1 ### (i) โ–พ
โœ“ Solution

$$ 0 $$

(ii) Undefined

---

Q.2 ### (i) โ–พ
โœ“ Solution

$$ 0.7 $$

(ii) Undefined

---

Q.3 ### (i) โ–พ
โœ“ Solution

Parallel

(ii) Perpendicular

---

Q.4 $$ โ–พ
โœ“ Solution

p=4 $$

---

Q.5 $$ โ–พ
โœ“ Solution

3x+4y+7=0 $$

---

Q.6 $$ โ–พ
โœ“ Solution

2x+5y-2=0 $$

---

Q.7 Altitude through $A$: โ–พ
โœ“ Solution

$$ 2x+5y+6=0 $$

Altitude through $B$:

$$ 5x+y-48=0 $$

---

Q.8 $$ โ–พ
โœ“ Solution

5x-3y-8=0 $$

---

Q.9 $$ โ–พ
โœ“ Solution

13x+5y-18=0 $$

---

Q.10 $$ โ–พ
โœ“ Solution

49x+28y-156=0 $$

---

Q.11 $$ โ–พ
โœ“ Solution

31x+15y+30=0 $$

---

Q.12 $$ โ–พ
โœ“ Solution

4x+13y-9=0 $$

# UNIT 5 : Coordinate Geometry # Multiple Choice Questions

Mathematics : Coordinate Geometry: Multiple choice questions with answers / choose the correct answer with answers - Maths Book back 1 mark questions and answers with solution for Exercise Problems

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# Multiple Choice Questions

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Q.1 The area of triangle formed by the points โ–พ
โœ“ Solution

Base $=10$

Height $=5$

$$ \text{Area}=\frac12\times10\times5 $$

$$ =25 $$

### Answer

$$ \boxed{(2)\ 25\text{ sq.units}} $$

---

Q.2 A man walks near a wall, such that the distance between him and the wall is 10 units. โ–พ
โœ“ Solution

Distance from Y-axis is constant.

Hence:

$$ x=10 $$

### Answer

$$ \boxed{(1)\ x=10} $$

---

Q.3 The straight line given by the equation โ–พ
โœ“ Solution

$$ \boxed{(2)\ \text{parallel to Y-axis}} $$

---

Q.4 If โ–พ
โœ“ Solution

For collinear points:

$$ \frac{p-7}{3-5}=\frac{6-7}{6-5} $$

$$ \frac{p-7}{-2}=-1 $$

$$ p-7=2 $$

$$ p=9 $$

### Answer

$$ \boxed{(3)\ 9} $$

---

Q.5 The point of intersection of โ–พ
โœ“ Solution

Add equations:

$$ 4x=12 $$

$$ x=3 $$

Then:

$$ y=5 $$

### Answer

$$ \boxed{(3)\ (3,5)} $$

---

Q.6 The slope of the line joining โ–พ
โœ“ Solution

$$ \frac{a-3}{4-12}=\frac18 $$

$$ \frac{a-3}{-8}=\frac18 $$

$$ a-3=-1 $$

$$ a=2 $$

### Answer

$$ \boxed{(4)\ 2} $$

---

Q.7 The slope of the line which is perpendicular to a line joining the points โ–พ
โœ“ Solution

Slope of given line:

$$ \frac{8-0}{-8-0}=-1 $$

Perpendicular slope:

$$ 1 $$

### Answer

$$ \boxed{(2)\ 1} $$

---

Q.8 If slope of the line $PQ$ is โ–พ
โœ“ Solution

Perpendicular slope:

$$ -\frac1{1/\sqrt3} $$

$$ =-\sqrt3 $$

### Answer

$$ \boxed{(2)\ -\sqrt3} $$

---

Q.9 If $A$ is a point on the Y-axis whose ordinate is $8$ and $B$ is a point on the X-axis whose abscissa is $5$, then the equation of the line $AB$ is โ–พ
โœ“ Solution

Intercept form:

$$ \frac{x}{5}+\frac{y}{8}=1 $$

$$ 8x+5y=40 $$

### Answer

$$ \boxed{(1)\ 8x+5y=40} $$

---

Q.10 The equation of a line passing through the origin and perpendicular to the line โ–พ
โœ“ Solution

Given slope:

$$ \frac73 $$

Perpendicular slope:

$$ -\frac37 $$

Passing through origin:

$$ y=-\frac37x $$

$$ 3x+7y=0 $$

### Answer

$$ \boxed{(3)\ 3x+7y=0} $$

---

Q.11 Consider four straight lines โ–พ
โœ“ Solution

Slopes:

$$ m_1=\frac43 $$

$$ m_2=\frac34 $$

$$ m_3=-\frac34 $$

$$ m_4=-\frac43 $$

Since:

$$ m_2\times m_4=-1 $$

they are perpendicular.

### Answer

$$ \boxed{(3)\ l_2 \text{ and } l_4 \text{ are perpendicular}} $$

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Q.12 A straight line has equation โ–พ
โœ“ Solution

$$ y=\frac12x+\frac{21}{8} $$

Slope:

$$ 0.5 $$

Intercept:

$$ 2.625\approx2.6 $$

### Answer

$$ \boxed{(1)} $$

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Q.13 When proving that a quadrilateral is a trapezium, it is necessary to show โ–พ
โœ“ Solution

$$ \boxed{(2)} $$

---

Q.14 When proving that a quadrilateral is a parallelogram by using slopes you must find โ–พ
โœ“ Solution

$$ \boxed{(2)} $$

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Q.15 $$ โ–พ
โœ“ Solution

Check option (2):

$$ 2+1=3 $$

$$ 3(2)+1=7 $$

Both satisfy.

### Answer

$$ \boxed{(2)} $$

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# Answer Key

| Q.No | Answer | |---|---| | 1 | 2 | | 2 | 1 | | 3 | 2 | | 4 | 3 | | 5 | 3 | | 6 | 4 | | 7 | 2 | | 8 | 2 | | 9 | 1 | | 10 | 3 | | 11 | 3 | | 12 | 1 | | 13 | 2 | | 14 | 2 | | 15 | 2 | # UNIT 5 : Coordinate Geometry


Ex 5.UEUnit Exercise10 questions
Q.1 PQRS is a rectangle formed by joining the points โ–พ
โœ“ Solution

Rhombus

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Q.2 The area of a triangle is $5$ sq.units. โ–พ
โœ“ Solution

$$ \left(\frac72,\frac{13}2\right) $$

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Q.3 Find the area of a triangle formed by the lines โ–พ
โœ“ Solution

$$ 0\text{ sq.units} $$

---

Q.4 If vertices of a quadrilateral are at โ–พ
โœ“ Solution

$$ k=-5 $$

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Q.5 Without using distance formula, show that the points โ–พ
โœ“ Solution

Find slopes:

Slope of line joining

$$ (-2,-1)\text{ and }(4,0) $$

$$ =\frac{0+1}{4+2} =\frac16 $$

Slope of line joining

$$ (3,3)\text{ and }(-3,2) $$

$$ =\frac{2-3}{-3-3} =\frac{-1}{-6} =\frac16 $$

Hence opposite sides are parallel.

Similarly,

Slope of line joining

$$ (4,0)\text{ and }(3,3) $$

$$ =\frac{3-0}{3-4} =-3 $$

Slope of line joining

$$ (-2,-1)\text{ and }(-3,2) $$

$$ =\frac{2+1}{-3+2} =-3 $$

Hence both pairs of opposite sides are parallel.

Therefore the quadrilateral is a parallelogram.

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Q.6 Find the equations of the lines, whose sum and product of intercepts are $1$ and $-6$ respectively. โ–พ
โœ“ Solution

$$ 2x-3y-6=0 $$

$$ 3x-2y+6=0 $$

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Q.7 The owner of a milk store finds that, he can sell $980$ litres of milk each week at โ‚น14/litre and $1220$ litres of milk each week at โ‚น16/litre. โ–พ
โœ“ Solution

$$ 1340\text{ litres} $$

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Q.8 Find the image of the point โ–พ
โœ“ Solution

$$ (-1,-4) $$

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Q.9 Find the equation of a line passing through the point of intersection of the lines โ–พ
โœ“ Solution

$$ 13x+13y-6=0 $$

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Q.10 A person standing at a junction (crossing) of two straight paths represented by the equations โ–พ
โœ“ Solution

$$ 119x+102y-125=0 $$

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# Answer Key

| Q.No | Answer | |---|---| | 1 | Rhombus | | 2 | $(7/2,\ 13/2)$ | | 3 | $0$ sq.units | | 4 | $-5$ | | 5 | Parallelogram | | 6 | $2x-3y-6=0,\ 3x-2y+6=0$ | | 7 | $1340$ litres | | 8 | $(-1,-4)$ | | 9 | $13x+13y-6=0$ | | 10 | $119x+102y-125=0$ |


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