Chapter 1, Problem 13PT

To determine

Find the measurement of angle

Answer to Problem 13PT

Value of $\angle X=139.5$ .

Explanation of Solution

Given information:

  $\angle X$ is 18 more than 3 times the measure of it’s compliment.

Formula used:

  $\angle X+\angle X\text{'}=180°$

Calculation:

Using formula,

  $\angle X\text{'}=180°-\angle X$ .........(1)

According to question,

  $\angle X-18=3(\angle X\text{'})$

Substituting value from (1)

  $\angle X-18=3(180°-\angle X)$

Solving,

  $\angle X-18=540-3\angle X$

Adding $3\angle X$ to both sides,

  $3\angle X+\angle X-18=540$

So,

  $4\angle X=540+18$

Dividing equation by 4,

  $\angle X=139.5$

Hence, value of $\angle X=139.5$ .