Find the value of x using supplementary angles

The video tutorial explains how to find the value of X in a geometry problem involving a triangle and supplementary angles. It begins by identifying the given information and the need to use supplementary angles, which add up to 180 degrees. The instructor sets up an equation using the given angles and solves it step-by-step to find the value of X, which is 21.

What is the sum of all angles inside a triangle?

What do we call angles that add up to 180 degrees?

How can you express the equation for the angles given in the problem?

What is the first step to solve the equation 8X + 12 = 180?

What is the final value of X after solving the equation?