Chapter 2.2, Problem 14WE

To determine

To prove: $m\angle 1=m\angle 2$ using two column method.

Explanation of Solution

Given:

The given figure is,

  

And the conditions are,

  $m\angle SRT=m\angle STR\text{and }m\angle 3=m\angle 4$

Statement	Reason
$m\angle SRT=m\angle STR\text{and }m\angle 3=m\angle 4$	Given
$m\angle 1+m\angle 3=m\angle 2+m\angle 4$	Since from the figure,   $\begin{array}{l}m\angle 1+m\angle 3=m\angle SRT\text{and}\\ m\angle 2+m\angle 3=m\angle STR\end{array}$
$m\angle 1=m\angle 2$	Since $m\angle 3=m\angle 4$ So they cancelled out