Given that a, B and C are the three sides of △ ABC, and a + B + C = 60cm, a: B: C = 3:4:5, the area of △ ABC is obtained

Given that a, B and C are the three sides of △ ABC, and a + B + C = 60cm, a: B: C = 3:4:5, the area of △ ABC is obtained


∵ a + B + C = 60cm, a: B: C = 3:4:5, ∵ a = 15cm, B = 20cm, C = 25cm. ∵ 152 + 202 = 252, ∵ ABC is a right triangle. The area of ∵ ABC is 12 × 15 × 20 = 150