3angles form a straight line. 1 angle measures 90 degrees another angle measures 26 degrees. what is the measure of the 3rd angle?

A straight line, also known as a supplementary line, is exactly 180 degrees. So if one angle is 90 degrees and the other is 26, the remaining third angle would have to be 64 degrees using this equation: 180-(90+26)
                                                           =180-116
                                                           =64 degrees