Question

求第十题怎么做

Answer 1

∠b = ∠a + 15°；∠c = ∠b +60° = ∠a + 15° + 60° = ∠a + 75°
又 ∠a + ∠b + ∠c = 180°
∴ ∠a + ∠a + 15° + ∠a + 75° = 180°
即： 3∠a = 90°
∴ ∠a = 30°
∠b = 30° + 15° = 45°
∠c = 45° + 60° = 105°

Answer 2

〈A=30度，〈B=45度，B-A=15，c-B=60则c-A=75又因A=180-(B+c)=90-2A，则A=30

追问

对不起啊有人先答了