已知:△ABC,如图,若P点是∠ABC和∠ACB的角平分线的交点,求证:∠P=90°+1/2∠A.
问题描述:
已知:△ABC,如图,若P点是∠ABC和∠ACB的角平分线的交点,求证:∠P=90°+
∠A.1 2
答
证明:∵P点是∠ABC和∠ACB的角平分线的交点,
∴∠PBC+∠PCB=
(∠ABC+∠ACB)=1 2
(180°-∠A)=90°-1 2
∠A.1 2
∴∠P=180°-
(∠ABC+∠ACB)=180°-90°+1 2
∠A=90°+1 2
∠A.1 2