Question

In parallelogram $ABCD$,
Which of the following option is correct?

• A. $m\angle C={120}^{\circ }$
• B. $m\angle A={120}^{\circ }$
• C. $m\angle B={60}^{\circ }$
• D. All of the above

Answer 1

The correct option is D All of the above


Concept: Sum of measures of adjacent angles of a parallelogram equals ${180}^{\circ }$

$\because m\angle C$ is adjacent to $m\angle D$ and $m\angle B$

$\therefore m\angle C+m\angle D={180}^{\circ }\Rightarrow m\angle C={180}^{\circ }-{60}^{\circ }={120}^{\circ }$

Concept: Measure of opposite angles of a parallelogram are equal.

$\therefore m\angle D=m\angle B={60}^{\circ }m\angle C=m\angle A={120}^{\circ }$