Question

In a parallelogram ABCD $\angle A={60}^o$find the other three angles.

Answer 1

$\angle A=\angle C={60}^o\left(Sinceoppositeanglesareequalin||gm\right)\angle B=\angle D⟹2\angle B={360}^o-{120}^o⟹\angle B={120}^o=\angle D$