Maths (Coordinate Geometry) : Class 10 Maths
















 








1. Find the area of the triangle whose vertices are A(2,4), B(−3,7) and C(−4,5).


A(2,4), B(−3,7) āφ⧰⧁ C(−4,5) āĻŦāĻŋāĻ¨ā§āĻĻ⧁⧰⧇ āĻ—āĻ āĻŋāϤ āĻ¤ā§ā§°āĻŋāϭ⧁āϜ⧰ āĻ•ā§āώ⧇āĻ¤ā§ā§°āĻĢāϞ āĻ•āĻŋāĻŽāĻžāύ?


Options:


Options: (a) 11 sq units  (b) 22 sq units  (c) 7 sq units  (d) 6.5 sq units


Ans: (d) 6.5 sq units


Soln


Area = 1​/2 âˆŖx1​(y2​-y3​) + x2​(y3​-y1​) + x3​(y1​- y2​)


=1​/2[2(7-5) + (-3)(5-4)+(−4)(47)]


=1/2[43+12]


=1/2​(13)


= 6.5



2.Find the area of the triangle whose vertices are A(10,−6), B(2,5) and C(−1,3).


A(10,−6), B(2,5) āφ⧰⧁ C(−1,3) āĻŦāĻŋāĻ¨ā§āĻĻ⧁⧰⧇ āĻ—āĻ āĻŋāϤ āĻ¤ā§ā§°āĻŋāϭ⧁āϜ⧰ āĻ•ā§āώ⧇āĻ¤ā§ā§°āĻĢāϞ āĻ•āĻŋāĻŽāĻžāύ?


Options: (a) 12.5  (b) 24.5  (c) 7  (d) 6.5


Ans: (b) 24.5 sq units


Soln


= 1​/2 [10(53)+2(3+6)+(1)(65)]



=1​/2 [20+18+11]


24.5


3. Find the area of the triangle whose vertices are A(4,4), B(3,−16) and C(3,−2).


A(4,4), B(3,−16) āφ⧰⧁ C(3,−2) āĻŦāĻŋāĻ¨ā§āĻĻ⧁⧰⧇ āĻ—āĻ āĻŋāϤ āĻ¤ā§ā§°āĻŋāϭ⧁āϜ⧰ āĻ•ā§āώ⧇āĻ¤ā§ā§°āĻĢāϞ āĻ•āĻŋāĻŽāĻžāύ ?


Options:


Options: (a) 12.5  (b) 24.5  (c) 7  (d) 6.5


Ans: (c) 7 sq units


Soln
Points B and C have same x-coordinate → vertical line.
Base = |−16 − (−2)| = 14
Height = |4 − 3| = 1


Area = 1/2 × 14 × 1 = 7


4. For what value of x are the points A(−3, 12), B(7, 6) and C(x, 9) collinear ?

A(−3,12), B(7,6) āφ⧰⧁ C(x,9) āĻŦāĻŋāĻ¨ā§āĻĻ⧁āĻŦā§‹ā§° āĻāϕ⧇ āϏāϰāϞ⧰⧇āĻ–āĻžāϤ āĻĨāĻžāĻ•āĻŋāĻŦāϞ⧈ x ā§° āĻŽāĻžāύ āĻ•āĻŋāĻŽāĻžāύ ?

Options: (a) 1  (b) −1  (c) 2  (d) −2


Ans: (c) 2


Soln
Slope AB = −3/5, Slope AC = −3/(x+3)


   3​/5 = - 3/x+3


⇒ x + 3 = 5


⇒ x = 2​


5. For what value of y are the points A(1,4), B(3,y) and C(−3,16) collinear ? 

A(1,4), B(3,y) āφ⧰⧁ C(−3,16) āĻŦāĻŋāĻ¨ā§āĻĻ⧁āĻŦā§‹ā§° āĻāϕ⧇ āϏāϰāϞ⧰⧇āĻ–āĻžāϤ āĻĨāĻžāĻ•āĻŋāĻŦāϞ⧈ y ā§° āĻŽāĻžāύ āĻ•āĻŋāĻŽāĻžāύ ?


Options: (a) 1  (b) −1  (c) 2  (d) −2


Ans: (d) −2


Soln
Slope AC = −3, Slope AB = (y−4)/2


y - 4​/2 = 3


y = 2


6. Find the value of p for which A(−1,3), B(2,p) and C(5,−1) are collinear.

A(−1,3), B(2,p) āφ⧰⧁ C(5,−1) āĻāϕ⧇ āϏāϰāϞ⧰⧇āĻ–āĻžāϤ āĻĨāĻžāĻ•āĻŋāĻŦāϞ⧈ p ā§° āĻŽāĻžāύ āĻ•āĻŋāĻŽāĻžāύ ?

Options: (a) 1  (b) −1  (c) 2  (d) −2


Ans: (a) 1


Soln
Slope AC = −2/3, Slope AB = (p−3)/3


p3​/3 = 2/3 ​p = 1


7. What is the midpoint of the line joining (−3,4) and (10,−5) ?

(−3,4) āφ⧰⧁ (10,−5) āϝ⧋āĻ— āϕ⧰āĻž āϰ⧇āĻ–āĻžāĻ‚āĻļā§° āĻŽāĻ§ā§āϝāĻŦāĻŋāĻ¨ā§āĻĻ⧁ āĻ•āĻŋāĻŽāĻžāύ ?


Options: (a) (−13,−9)  (b) (−6.5,−4.5)  (c) (3.5,−0.5)  (d) none


Ans: (c) (3.5, −0.5)


Soln


M = (−3+10​/2 , 45/2​) = (3.5, 0.5)


8. A line passes through (3,4) and (5,6). Find the ordinate of the point whose abscissa is −1.

(3,4) āφ⧰⧁ (5,6) āĻŦāĻŋāĻ¨ā§āĻĻ⧁⧰⧇ āĻ¯ā§‹ā§ąāĻž āϰ⧇āĻ–āĻžāϤ x = −1 āĻšāϞ⧇ y āĻ•āĻŋāĻŽāĻžāύ?

Options: (a) 1  (b) −1  (c) 2  (d) 0


Ans: (d) 0


Soln
Slope = 1 ⇒ Equation: y = x + 1
x = −1 ⇒ y = 0


9. If the distance between (8,p) and (4,3) is 5, find p.


Options: (a) 6  (b) 0  (c) both (a) and (b)  (d) none


Ans: (c) both


Soln


(8 - 4)2 + (p - 3)2=25 (p - 3)2 = 9 p = 6 or 0


 (8,p) āφ⧰⧁ (4,3) āĻŽāĻžāϜ⧰ āĻĻā§‚ā§°āĻ¤ā§āĻŦ 5 āĻšāϞ⧇ p ā§° āĻŽāĻžāύ āĻ•āĻŋāĻŽāĻžāύ ?


10. Find the fourth vertex of a rectangle whose three vertices in order are (4,1), (7,4) and (13,−2).

(4,1), (7,4) āφ⧰⧁ (13,−2) āϤāĻŋāύāĻŋāϟāĻž āĻ•ā§ā§°āĻŽ āĻ…āύ⧁āϏ⧰āĻŋ āĻĻāĻŋāϝāĻŧāĻž āĻĨāĻžāĻ•āĻŋāϞ⧇ āĻ†ā§ŸāϤāĻ•ā§āώ⧇āĻ¤ā§ā§°ā§° āϚāĻ¤ā§ā§°ā§āĻĨ āĻŦāĻŋāĻ¨ā§āĻĻ⧁ āĻ•āĻŋāĻŽāĻžāύ?

Options: (a) (10,−5)  (b) (10,5)  (c) (8,3)  (d) (8,−3)


Ans: (a) (10, −5)


Soln



11. If four vertices of a parallelogram in order are (−3,−1), (a,b), (3,3) and (4,3), find a:b.

āϏāĻŽāĻžāĻ¨ā§āϤ⧰āϭ⧁āϜ⧰ āĻ•ā§ā§°āĻŽ āĻ…āύ⧁āϏ⧰āĻŋ āϚāĻžā§°āĻŋāϟāĻž āĻļā§€ā§°ā§āώāĻŦāĻŋāĻ¨ā§āĻĻ⧁ (−3,−1), (a,b), (3,3) āφ⧰⧁ (4,3) āĻšāϞ⧇ a:b āĻ•āĻŋāĻŽāĻžāύ ?

Options: (a) 1:4  (b) 4:1  (c) 1:2  (d) 2:1


Ans: (b) 4 : 1


Soln
Diagonal midpoints equal (āĻĻ⧁āϟāĻž āĻ•ā§°ā§āĻŖā§° āĻŽāĻ§ā§āϝāĻŦāĻŋāĻ¨ā§āĻĻ⧁ āĻāϕ⧇ āĻšāϝāĻŧāĨ¤) ⇒ a = −4, b = −1 ⇒ a:b = 4:1


12. Find the area of the triangle formed by (1,4), (3,2) and (−3,16).

(1,4), (3,2) āφ⧰⧁ (−3,16) āĻŦāĻŋāĻ¨ā§āĻĻ⧁⧰⧇ āĻ—āĻ āĻŋāϤ āĻ¤ā§ā§°āĻŋāϭ⧁āϜ⧰ āĻ•ā§āώ⧇āĻ¤ā§ā§°āĻĢāϞ āĻ•āĻŋāĻŽāĻžāύ?

Options: (a) 40  (b) 48  (c) 24  (d) none


Ans: (d) none


Soln
Area = 8 sq units, āϝāĻŋ āĻŦāĻŋāĻ•āĻ˛ā§āĻĒāϤ āύāĻžāχāĨ¤


Let the three points be : A(1, 4), B(3, 2), C(−3, 16)


1st: Use the area formula of a triangle: Area = 1/2âˆŖx1(y2y3)+x2(y3−y1)+x3(y1−y2)âˆŖ


2nd : Substitute the values


=1/2[1(2 -16) + 3(16 - 4) + (−3)(4−2)]


3rd: Simplify


=1/2[1(-14)+3(12)+(−3)(2)]


= 1/2​[14+366]


= 1/2​*16


Ans: Area = 8 square units


13. The points (2,5), (4,1) and (6,−7) form which type of triangle ?

(2,5), (4,1) āφ⧰⧁ (6,−7) āĻŦāĻŋāĻ¨ā§āĻĻ⧁āĻŦ⧋⧰⧇ āĻ•āĻŋāϧ⧰āĻŖā§° āĻ¤ā§ā§°āĻŋāϭ⧁āϜ āĻ—āĻ āύ āϕ⧰⧇ ?

Options: (a) isosceles  (b) equilateral  (c) scalene  (d) right-angled


Ans: (c) scalene


Soln
āϤāĻŋāύāĻŋāĻ“ āĻŦāĻžāĻšā§ā§° āĻĻā§ˆā§°ā§āĻ˜ā§āϝ āĻ­āĻŋāĻ¨ā§āύ ⇒ Scalene triangle


14. Area = 70 sq units


The area of the triangle formed by (p, 2−2p), (1−p,2p) and (−4−p, 6−2p) is 70 sq units. How many integral values of p are possible ?



(p,2 - 2p), (1 - p,2p) āφ⧰⧁ (-4 -p,6 -2p) āĻŦāĻŋāĻ¨ā§āĻĻ⧁⧰⧇ āĻ—āĻ āĻŋāϤ āĻ¤ā§ā§°āĻŋāϭ⧁āϜ⧰ āĻ•ā§āώ⧇āĻ¤ā§ā§°āĻĢāϞ 70 āĻšāϞ⧇ p ā§° āĻ•āĻŋāĻŽāĻžāύāϟāĻž āĻĒā§‚ā§°ā§āĻŖāϏāĻ‚āĻ–ā§āϝāĻž āĻŽāĻžāύ āϏāĻŽā§āĻ­ā§ą?

Options: (a) 2  (b) 3  (c) 4  (d) none


Ans: (a) 2


Soln


âˆŖ14(p - 4)âˆŖ = 70 âˆŖp4âˆŖ = 5


p = 9 āĻŦāĻž 1


2 values


15. If the origin is the midpoint of the line joining (2,3) and (x,y), find (x,y).

(2,3) āφ⧰⧁ (x,y) āϝ⧋āĻ— āϕ⧰āĻž āϰ⧇āĻ–āĻžāĻ‚āĻļā§° āĻŽāĻ§ā§āϝāĻŦāĻŋāĻ¨ā§āĻĻ⧁ āϝāĻĻāĻŋ āĻŽā§‚āϞāĻŦāĻŋāĻ¨ā§āĻĻ⧁ (0,0) āĻšāϝāĻŧ, āϤ⧇āĻ¨ā§āϤ⧇ (x,y) āĻ•āĻŋāĻŽāĻžāύ ?

Options: (a) (2,-3)  (b) (2,3)  (c) (-2,3)  (d) (-2,-3)


Ans: (d) (-2, -3)


Soln


2 + x​ / 2 = x = 2,


3 + y / 2 ​= y = 3