Question

If m<10=77, m<7=47 and m<16=139, find the measure of the missing angle m<9=?

Answer 1

we have angle 9 and angle 10 are collateral angles, this means that they are supplementary, i.e. they add up to 180°. Therefore:

`\begin{gathered} m\angle9+m\angle10=180 \\ m\angle9+77=180 \\ m\angle9+77-77=180-77 \\ m\angle9=103 \end{gathered}`

answer: m<9 = 103°