Question

In a triangle PQR; QR = PR and ∠P = 36^o. Which is the largest side of the triangle?

Answer 1

In ΔPQR,
QR = PR      ...[ Given ]
∴ ∠P = ∠Q  ...[ angles opposite to equal sides are equal ]
⇒ ∠P = 36° ..[Given]
⇒ ∠Q = 36°

In ΔPQR,
∠P + ∠Q + ∠R = 180°
⇒ 36° + 36° + ∠R = 180°
⇒ ∠R + 72° = 180°
⇒ ∠R = 108°

Now,
∠R = 108°
∠P = 36°
∠Q = 36°

Since ∠R is the greatest, therefore, PQ is the largest side.