Question

Angles Q and R of a ΔPQR are 25° and 65°.

Write which of the following is true:

Options

• PQ² + QR² = RP²

• PQ² + RP² = QR²

• RP² + QR² = PQ²

Answer 1

PQ² + RP² = QR²

Explanation:

The sum of the measures of all interior angles of a triangle is 180º.

∠PQR + ∠PRQ + ∠QPR = 180°

25° + 65° + ∠QPR = 180°

90° + ∠QPR = 180°

∠QPR = 180° − 90°

∠QPR = 90°

Therefore, ΔPQR is right-angled at point P.

Hence, (PR)² + (PQ)² = (QR)²

Thus, (ii) is true.