Question

ray ce is the angle bisector of ∠acd. which statement about the figure must be true? o m∠ecd = 1/2m∠ecb o m∠ace = 1/2m∠acd o ∠ace ≅ ∠dcb o ∠ecd ≅ ∠acd

Explanation:

Step1: Recall angle - bisector definition

An angle - bisector divides an angle into two equal angles. If ray $CE$ is the angle - bisector of $\angle ACD$, then $m\angle ACE=m\angle ECD$ and $m\angle ACE=\frac{1}{2}m\angle ACD$, $m\angle ECD=\frac{1}{2}m\angle ACD$.

Answer:

B. $m\angle ACE=\frac{1}{2}m\angle ACD$