Question

In the diagram below angle AED=(4n-20)° and angle BEC=(2n-16)°. What is the measure of angle CED in degrees

Answer 1

Check the picture below.

so, bearing in mind that vertical angles are equal, thus ∡AED = ∡BEC, and we know that ∡BEC = 52 = ∡AED, so those two angles added up are 104°.

now, a circle has a total of 360°, if we take away those 104° from the red angles, what's leftover is just 256°, well, the green angles there are also vertical angles and thus twins, so each one will take half of 256°.

∡BEA = 128° = ∡CED.