Question

中学数学题一道△ABC中,∠A+∠C=2∠B,∠A=42°,则∠B=___,∠C=____.

Answer 1

∠A+∠B+∠C=180

(∠A+∠C)+∠B=180

2∠B+∠B=180

3∠B=180

∠B=60

∠A=42

∠C=180-60-42=78