Question

Find the missing angle on a quadrilateral. Angle C equals 80 degrees, Angle D equals 90 degrees, and angle E equals 135 degrees. What is the measure of Angle F?

Answer 1

All quadrilateral angles have to add up to a total of 360°, so we just need to add the angles we already have and subtract that from 360.
135+90+80=305
360-305=55 so your answer is 55!