Question

Find the measure of all the angles of parallelogram ABCD, if angle D is 60degree.​

Answer 1

If <D is 60°, then <B will be also 60°.

[opposite angles of a parallelogram are equal]

so <A=<C.

We know that <A+<D=180° (sum of two adjacent angles in parallelogram is 180°)

<A+60°=180°

<A=120°

so <C = 120°

Answer 2

Answer:

We know that sum of Adjacent angles of parallelogram is 180°

∴ ∠A+∠D=180°

⟹∠A+60° =180°

∴∠A=180° −60° =120°