Question

State the measure of each angle.

• $\angle COF$
  

Short answer

The measure of$\angle COF$ is $\mathbf{30}\mathbf{°}$.

Step-by-step solution

Step 1. Apply protractor postulate.

On $\overline{AH}$in a given plane, choose any point O between A and B.

Consider rays, $\overline{OA}$and $\overline{OH}$which are drawn from point O on $\overline{AH}$.

These rays results in pairing with the angles from 0 to 180 in such a way that:

The line $\overline{OA}$is paired with 0, and $\overline{OH}$with 180.

If $\overline{OC}$ is paired with x, and $\overline{OF}$with y, then $m\angle COF=\left|x-y\right|$.

Step 2. Observe the figure below and write the values of OG and OF.

It can be observed from the figure that, $\overline{OC}$is 90 and $\overline{OF}$is 120.

Step 3. Calculate m∠COF

$\begin{array}{l}m\angle COF=\left|90-120\right|\\ =\left|-30\right|\\ =30°\end{array}$