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 - measure angles. Since ray $CE$ is the angle bisector of $\angle ACD$, it means $\angle ACE$ and $\angle ECD$ are equal, and each is half of $\angle ACD$. That is $m\angle ACE=m\angle ECD=\frac{1}{2}m\angle ACD$.

Answer:

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