Question

question 15 (multiple choice worth 4 points) (02.03k mc) britton rotated trapezoid abcd 180° on the coordinate plane. if angle b is 20° and angle d is 90°, what is the degree measurement of angle b? 20° 70° 90° 180°

Explanation:

Step1: Recall rotation property

A $180^\circ$ rotation is a rigid transformation, so it preserves angle measures.

Step2: Match original and rotated angle

Since angle $B = 20^\circ$, its image angle $B'$ has the same measure.
$\text{Measure of } \angle B' = 20^\circ$

Answer:

A. $20^\circ$