Question

problem 16: find x. (first taught in lesson 30)

Explanation:

Step1: Find the supplementary angle

The angle adjacent to $105^{\circ}$ is $180 - 105=75^{\circ}$ since they are supplementary.

Step2: Use angle - sum property of a triangle

In a triangle, the sum of interior angles is $180^{\circ}$. Let the three angles of the triangle be $50^{\circ}$, $75^{\circ}$, and $x^{\circ}$. So, $50 + 75+x=180$.

Step3: Solve for $x$

$125 + x=180$, then $x=180 - 125=55$.

Answer:

$x = 55$