Question

set up an equation for your exterior angle, then use multi-step equation steps to solve for y.A. 15B. 17.4C. 5D. 10

Answer 1

In any triangle, the sum of the interior angles of two vertices is equal to the exterior angle of the other vertex.

Using this property, we can write the following equation:

`\begin{gathered} \text{ABC+BAC=ACD}_{} \\ (4y+8)+(5y+3)=146 \\ 9y+11=146 \\ 9y=146-11 \\ 9y=135 \\ y=(135)/(9) \\ y=15 \end{gathered}`

The value of y is equal to 15, therefore the correct option is A.