Question

在△ABC中,∠A-∠B=∠B-∠C,∠A:∠C=2:1,试判断△ABC的形状

Answer 1

∠A-∠B=∠B-∠C

=>∠A+∠C=2∠B

=>180-∠B=2∠B

=>180=3∠B

=>∠B=60

=>

∠A+∠C=120

∠A:∠C=2:1

=>

∠A=2∠C

=>3∠C=120

=>∠C=40

=>∠A=80

所以是锐角三角形