Question 1085821


A parallelogram is quadrilateral comprised of two pairs of parallel lines.
Opposite angles are congruent.


if ∠ {{{A=120}}}°, then ∠ {{{C=120}}}° too since they are opposite angles

same is with ∠ {{{B}}} and ∠ {{{D}}};∠ {{{B=D}}}

since the sum of all angles is {{{360}}}°, we have

∠ {{{120+B+120+D=360}}}° 

∠ {{{B+B=360-240}}}° 

∠ {{{2B=120}}}° 

∠ {{{B=60}}}° =>∠ {{{D=60}}}°