Chapter 7, Problem 9RP

To determine

To calculate : The value of $m\angle YZA$

Answer to Problem 9RP

The value of $m\angle Z={130}^0$

Explanation of Solution

Given information : The following can be interpreted from the figure

  $m\angle A+m\angle Y=m\angle Z$

Formula used : Sum of two interior angles is equal to the measure of the exterior angle of the other interior angle

Calculation : We substitute the values of angles A , Y and Z from the figure, thus we get

  ${40}^0+(x+{50}^0)=2x+{50}^0\to x={40}^0$

Now, we substitute the value of x equal to ${40}^0$ in the angle Z , hence, we get

  $m\angle Z={130}^0$