Describing Angles

Let's first identify the angle we want. The symbol $\angle AOC$ refers to the angle found between the rays that start at $O$ and pass through the points $B$ and $D.$

Examining the protractor, we can see that the ray traveling through $A$ passes through $0^{\circ }.$ Also, the ray traveling through $C$ passes through $55^{\circ }.$ By the Protractor Postulate, the measure of $\angle AOC$ is the difference between $55^{\circ }$ and $0.$ $$m\angle AOC\text{:}55^{\circ }-0^{\circ }=55^{\circ }$$ Now, we can classify the angle using its measure.

Because our angle is $55^{\circ },$ we know that it is an acute angle.