Chapter 11, Problem 4CR

To determine

To find: The value of $\angle 1$ .

Answer to Problem 4CR

  $m\angle 1={68}^0$

Explanation of Solution

Given information:

  $m\angle 4={112}^0$

Given

  $m\angle 4={112}^0$

Since $\angle 4$ and $\angle 1$ are Supplementary, the sum of their measures is ${180}^0$

So,

  $m\angle 4+m\angle 1={180}^0$

  $\begin{array}{l}m\angle 4+m\angle 1={180}^0\\ \Rightarrow {112}^0+m\angle 1={180}^0\\ \Rightarrow {112}^0-{112}^0+m\angle 1={180}^0-{112}^0\\ \Rightarrow m\angle 1={68}^0\end{array}$

Therefore,

  $m\angle 1={68}^0$