BP,CP分别是∠ABC,∠ACB的平分线
∠P=180°-(∠B/2+∠C/2)=180°-(∠B+∠C)/2.(1)
∠A=180°-(∠B+∠C) → ∠A/2=90°-(∠B+∠C)/2.(2)
(1)式减(2)式
∠P-∠A/2=90°
∠P=90°+∠A/2
BP,CP分别是∠ABC,∠ACB的平分线
∠P=180°-(∠B/2+∠C/2)=180°-(∠B+∠C)/2.(1)
∠A=180°-(∠B+∠C) → ∠A/2=90°-(∠B+∠C)/2.(2)
(1)式减(2)式
∠P-∠A/2=90°
∠P=90°+∠A/2