It is known that △ ABC is an equilateral triangle, P is a point in the triangle, PA = 3, Pb = 4, PC = 5

It is known that △ ABC is an equilateral triangle, P is a point in the triangle, PA = 3, Pb = 4, PC = 5

Rotate △ ABP clockwise about point B for 60 ° to get △ BCQ, connect PQ, ∵ - PBQ = 60 °, BP = BQ, ∵ - bpq is equilateral triangle, ∵ PQ = Pb = 4, and PC = 5, CQ = 4. In △ PQC, pq2 + QC2 = PC2, ∵ PQC is right triangle, ∵ - BQC = 60 ° + 90 ° = 150 °, and ∵ - APB = 150 °