Question

angle r is a right angle. if a bisector were to be created in angle r, what would the measure of both congruent angles created be?
90°
70°
55°
45°

Explanation:

Step1: Recall right - angle measure

A right angle measures $90^{\circ}$.

Step2: Understand angle - bisector concept

An angle bisector divides an angle into two congruent (equal - measure) angles.

Step3: Calculate the measure of congruent angles

Let the measure of the right angle be $m\angle R = 90^{\circ}$. If it is bisected, then the measure of each of the two congruent angles is $\frac{90^{\circ}}{2}=45^{\circ}$.

Answer:

D. $45^{\circ}$