Question

In ΔPQR, PR = QR. ∠P = 2x – 10°, ∠R = x + 5°.

∴ The value of x is ______.

विकल्प

• 45°

• 39°

• 40°

• 42°

Answer 1

∴ The value of x is 39°.

Explanation:

1. Given:

PR = QR triangle is isosceles with equal sides PR and QR.

Therefore, ∠P = ∠Q.

∠P = 2x – 10°

∠R = x + 5°

2. Since PR = QR, the angles opposite them are equal:

So, ∠P = ∠Q

= 2x – 10°

3. Using the angle sum property of triangle:

∠P + ∠Q + ∠R = 180°

Substitute values:

(2x – 10) + (2x – 10) + (x + 5) = 180°

4x – 20 + x + 5 = 180°

5x – 15 = 180°

5x = 195°

x = 39°