How do you  estimate the measure of an angle?
<answer> In right triangle to measure the third angle add its measure to 90 and subtract that total from 180. <context> A right triangle is so named because one of its angles is a right angle. 1  The measure of the third angle. In this case, you add its measure to 90, the number of degrees in the right angle and subtract that total from 180.  The measure of any two of the triangle’s sides.