Greetings!
Answer:
a = 17
Explanation:
Because all the lines are congruent (same length) as indicted by the lines, this means that every angle is the same.
180 ÷ 3 = 60
So every angle is 60°
This also means that:
4a - 8 = 60
Isolate the 4a by moving the -8 over to the other side, making it a +8:
4a = 60 + 8
4a = 68
Now simply divide both sides by 4 to get the value of 1a:
a = 17
So a = 17
Hope this helps!