Question

what is m∠cbd?
a 60° 80° d 35° c
m∠cbd = °

Explanation:

Step1: Recall triangle angle sum

In $\triangle CBD$, angles sum to $180^\circ$. Angles are $\angle C = 35^\circ$, $\angle CDB = 180^\circ - 80^\circ = 100^\circ$ (linear pair).

Step2: Calculate $\angle CBD$

Let $m\angle CBD = x$. Then $x + 35^\circ + 100^\circ = 180^\circ$. Solve: $x = 180^\circ - 35^\circ - 100^\circ = 45^\circ$.

Answer:

$45$