Question

3) If Z8 and 29 are supplementary angles, and m29= 86°; find m28.

Answer 1

Supplementary angles add up to 180°.

So, you have

$\begin{gathered} \angle8+\angle9=180\text{\degree} \\ \angle9=86\text{\degree} \\ \angle8+86\text{\degree}=180\text{\degree} \\ \text{ Subtract 86\degree{}from both sides of the equation} \\ \angle8+86\text{\degree}-86\text{\degree}=180\text{\degree}-86\text{\degree} \\ \angle8=94\text{\degree} \end{gathered}$