If we take the measures of the angles p and q as x, we will notice that the angles m and n correspond to 5x and since it is a straight line, it must be 5x = 180 °
solving for x we obtain 36 °
and since the measures of p q and the angle we are looking for are a rectangle, they must add 90 °
To find the unknown measure we can subtract the measures of the angles p and q from 90 °, this is 90-36-36
The measure of the EBF angle must be 18°.
