A triangle has 2 known angles that are 30 degrees and 80 degrees. Find the value of the third angle.

A quadrilateral has 3 known angles with measures of 48 degrees, 79 degrees, and 100 degrees. What is value of the the fourth angle?

The sum of the internal angles of a n-sided polygon is equal to:

A pentagon has 4 known angles with measures of 125 degrees, 100 degrees, 48 degrees, and 76 degrees. What is the measure of the final angle?

In the figure below, AB // CD. Find the measure of x.