In Fig. 6.1, side QR of a ∆PQR has been produced to the point S. If ∠PRS = 115° and ∠P = 45°, then ∠Q is equal to
a. 70°
b. 105°
c. 51°
d. 80°

Solution:
Given, the side QR of a ∆PQR has been produced to the point S.
∠PRS = 115° and ∠P = 45°
We have to find the value of ∠Q.
We know that the sum of a linear pair of angles is equal to 180 degrees.
So, ∠R + 115° = 180°
∠R = 180° - 115°
∠R = 65°
We know that the sum of all three interior angles of a triangle is always equal to 180 degrees.
So, ∠P + ∠Q + ∠R = 180°
45° + ∠Q + 65° = 180°
110° + ∠Q = 180°
∠Q = 180° - 110°
Therefore, ∠Q = 70°
✦ Try This: In the given figure, ∠ACD is an exterior angle of ∆ABC. ∠B = 40°, ∠A = 70°. Find the measure of ∠ACD
☛ Also Check: NCERT Solutions for Class 7 Maths Chapter 6
NCERT Exemplar Class 7 Maths Chapter 6 Sample Problem 1
In Fig. 6.1, side QR of a ∆PQR has been produced to the point S. If ∠PRS = 115° and ∠P = 45°, then ∠Q is equal to, a. 70°, b. 105°, c. 51°, d. 80°
Summary:
In Fig. 6.1, side QR of a ∆PQR has been produced to the point S. If ∠PRS = 115° and ∠P = 45°, then ∠Q is equal to 70°
☛ Related Questions:
- In an equilateral triangle ABC (Fig. 6.2), AD is an altitude. Then 4AD² is equal to, a. 2BD², b. BC² . . . .
- Which of the following cannot be the sides of a triangle? a. 3 cm, 4 cm, 5 cm, b. 2 cm, 4 cm, 6 cm, . . . .
- Which one of the following is not a criterion for congruence of two triangles? a. ASA, b. SSA, c. SA . . . .
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