Question

Find the reference angle Sketch “ “ in standard position and label “ “

Answer 1

Solution:

Given that

$\theta=155\degree$

To evaluate the reference angle, we have

$\begin{gathered} \theta+\theta^{\prime}=180(sum\text{ of angles on a line\rparen} \\ \Rightarrow155+\theta^{\prime}=180 \\ add\text{ -155 to both sides} \\ -155+155+\theta^{\prime}=-155+180 \\ \Rightarrow\theta\text{'=25} \end{gathered}$

Hence, the reference angle is evaluated to be

$25\degree$