Question

I don't understand this​

Answer 1

Given that measure 2 is 79 degrees, we know it'll be supplementary to angle 1 meaning that that both angle measures 1 and 2 will equal 180 degrees:

79 + x = 180

-79 -79

x = 101, ∠1 = 101°

Angles 2 and 4 are vertical, so they are congruent meaning they measure the same degrees:

if ∠2 = 79, then ∠4 is also equal to 79°

Now that we found the measure of angle 1, we can determine the measure of angle 3 since they are vertical as well, (vertical angles are congruent, meaning they measure the same degrees):

if ∠1 = 101, then ∠3 is also equal to 101°