Chapter 3.3, Problem 63SPR

To determine

To calculate angle

  $m\angle 1$ .

Answer to Problem 63SPR

  $m\angle 1={123}^o$

Explanation of Solution

Given information:

In the figure

  $a\left|\right|b$

  $c\left|\right|d$

Figure

  $m\angle 4={57}^{°}$

Calculation:

Figure

  $m\angle 4={57}^{°}$

$m\angle 2$ and $m\angle 4$ are corresponding angles

Then

  $m\angle 2={57}^{°}$

$m\angle 1$ and $m\angle 2$ are suplementry angles

And sum of suplementry angle is ${180}^o$

Then

  $m\angle 1+m\angle 2={180}^o$

Substitute value of $m\angle 2$

  $m\angle 1+{57}^o={180}^o$

On solving

  $m\angle 1={180}^o-{57}^o$

On solving

  $m\angle 1={123}^o$