Question

△ABC中,∠A与∠B的和刚好等于∠C的二分之一,∠A比∠B大40°,求∠B

Answer 1

∠A+∠B=1/2∠C

1/2∠C+∠C=2/3∠C=180°

∠C=120°

∠A+∠B=1/2∠C=60°

∠A=∠B+40°

∠B+40°+∠B=60°

2∠B=20°

∠B=10°