Class 10 Maths - Revision Assignment Question Answers

Q 1. In triangle PQR right angled at Q, PQ = 3 cm and PR = 6 cm. Determine angle QPR and angle PRQ.

(a.)

60°, 30°

(b.)

30°, 60°

(c.)

45°, 45°

(d.)

None of these

Answer:

(i)

Q 2. If the point (6, 2) divides the line segment joining A(6, 5) and B(4, y) in the ratio of 3:1, then find the value of y

(a.)

(b.)

(c.)

(d.)

None of these

Answer:

(i)

Q 3. If in two triangles ABC and PQR AB/QR = BC/PR = CA/PQ, write two similar triangles

(a.)

∆ABC similar to area ∆QRP

(b.)

∆ABC similar to PQR

(c.)

∆ABC similar to PRQ

(d.)

None of these

Answer:

(i)

Q 4. In right angled triangle, with sides a and b and hypotnuse c, the altitude drawn on the hypotnuse is x. Then the correct solution is:

(a.)

ab = cx

(b.)

ax = bc

(c.)

a = cx

(d.)

None of these

Solution:

Given: AC = c, AB = a, BC = b, FB = x

Area of ∆ABC = (1/2) x AB x BC

= (1/2) x a x b -(i)

= (1/2) x FB x AC

= (1/2) x x x c -(ii)

From (i) and (ii)

(1/2)ab = (1/2)cx

=> ab = cx

Option (i) is correct

Q 5.

Assertion (A): If ∆ABC and ∆PQR are congruent triangles, then they are also similar triangles

Reason(R): If ∆ABC and ∆PQR are congruent triangles, then they are also similar triangles need not be congruent.

(a.)

Both Assertion (A) and Reason (R) are true and Reason (R) is correct explanation of Assertion (A)

(b.)

Both Assertion (A) and Reason (R) are true but Reason (R) is not correct explanation of Assertion (A)

(c.)

Assertion (A) is true but Reason (R) is false

(d.)

Assertion (A) is false but Reason (R) is true

Answer:

(a)

Revision Assignment 1: October

Q 1. Determine the ratio in which line 2x + y - 4 = 0, divides the line segment joining the points A(-2, 2) and B(3, 7).

Solution:

Let the line 2x + y - 4 = 0, divide the line segment joining the points A(2, -2) and B(3, 7) in the ratio K:1. Let the point of intersection be M.

Then M{(3k + 2)/(k + 1), (7k - 2)/(k + 1)}

M lies on the line 2x + y - 4 = 0

2{(3k + 2)/(k + 1)} + {(7k - 2)/(k + 1)} - 4 = 0

6k + 4 + 7k - 2 - 4(k + 1) = 0

=> 6k + 4 + 7k - 2 - 4k - 4 = 0

=> 9k - 2 = 0

=> k = 2/9

Hence, the required ratio is 2:9

Short Cut for JEE Main and MCQs

Q 1. The ratio in which the line divides the line ax + by + c divides the line segment joining the points (x₁, y₁) and (x₂, y₂) = - {(ax₁ + by₁ + c)/(ax₂ + by₂ + c)}

Solution:

-[{2(2) - 2 - 4}/{2(3) + 7 - 4}]

= -(-2/9)

= 2/9

or 2:9