Question

find the value of x.

Explanation:

Step1: Find the adjacent interior angle

The adjacent interior angle of $126^{\circ}$ is $180 - 126=54^{\circ}$ (linear - pair angles).

Step2: Use the triangle - angle sum property

In a triangle, the sum of interior angles is $180^{\circ}$. So $x + 54+81 = 180$.

Step3: Solve for $x$

$x=180-(54 + 81)=180 - 135 = 45$.

Answer:

$45$