Hello from MrBillDoesMath!
Answer:
40
Discussion:
A diagram is always appreciated!
Assuming that
mAOC = mAOB + mBOC =>
108 = (3x + 4) + (8x - 28) => combine common terms
108 = (3x + 8x) + (4 - 28 ) =>
108 = 11x - 24 => add 24 to both sides
132 = 11x =>
x = 132/11 = 12
So mAOB = 3x + 4 = 3(12) + 4 = 36 + 4 = 40
Thank you,
MrB
