O is the incentre of the ΔPQR. If ∠POR = 120 degree, then what is the ΔPOR ?
Answer & explanation
Correct answer: option 2
We know that,
Angle at incentre = 90° + \(\frac{ vertex \; angle }{2}\)
= ∠POR = 120°
= ∠POR = 90° + \(\frac{ ∠PQR }{2}\)
= 120° = 90 + \(\frac{ ∠PQR }{2}\)
= \(\frac{ ∠PQR }{2}\) = 120 - 90
= ∠PQR = 30° × 2 = 60°