In circle O, what is m? 84° 96° 120° 168°

The answer is 120

You can solve this with the Intersecting Secant Angles Theorem. That theorem says that:

∠ACE = (mAE - mBD) / 2

so

36 = (mAE - 48) / 2

so

mAE - 48 = 72 = > mAE = 72 + 48 = 120

The answer on e20 is 120