what is he value of a

Answer:
A. 78
Step-by-step explanation:
2a+24= 180
-24 -24
2a= 156
divide each side by 2
a= 78
Answer:
a = 52 -- READ EXPLANATION, YOU WON'T BE PREPARED FOR A TEST WITHOUT IT.
Step-by-step explanation:
We know 2a + 24 is on one side of a diameter line, along with <a
to find out what it is, we can do the equation (2a + 24) + a = 180
this would simplify as 3a + 24 = 180
180 - 24 = 156
156 / 3 = 52
so we now know that a = 52