What does a equal?
(don’t just give the answer pls explain)

hi <3
okay so there are a few rules you need to be aware of first:
- angles in a triangle sum to 180
- angles on a straight line sum to 180
so first, lets find the missing angle of the triangle:
180 - 80 - (a - 5) = 105 - a
now lets form an equation because we know that 180 subtract this angle equals 2a:
180 - (105 - a) = 2a
75 + a = 2a
subtract a from both sides:
a = 75
hope this helps :)
Answer:
the sum of two interior opposite angel is equal to the exterior angel