答:
三角形ABC中:∠A+∠B+∠C=180°,即:
50°+2∠PBC+2∠PCB=180°
所以:∠PBC+∠PCB=(180°-50°)/2=65°
故:
∠BPC
=180°-(∠PBC+∠PCB)
=180°-65°
=115°