Question

if mnop is a rectangle, and m∠mon = 60°, what is the value of x? a. 30 b. 60 c. 90 d. 45 e. 120 f. cannot be determined

Explanation:

Step1: Recall property of rectangle diagonals

In a rectangle, diagonals are equal and bisect each other. So $\angle MON$ and $\angle MOP$ are supplementary.

Step2: Calculate the value of $x$

Since $\angle MON = 60^{\circ}$, and $\angle MON+\angle MOP = 180^{\circ}$, then $x=\angle MOP=180 - 60$.
$x = 120^{\circ}$

Answer:

E. 120