若∠a=120°,且∠a的补角是∠β的3倍,则∠β=.

Question

若∠a=120°,且∠a的补角是∠β的3倍,则∠β=________.

Answer 1

∠a=120°,且∠a的补角是180-120=60
∠a的补角是∠β的3倍,即60=3∠β
所以∠β=60/3=20°