Note that angles EBA and ECD are equal right angles
And angle BEA = angle CED
So triangle EBA is similar to triangle ECD
So
BE / BA = CE / DC
BA = 12
Let EB = 20 - x
Let CE = x
DC = (12 + 9 + 9) - 27 = 3
So we have that
[20 - x] / 12 = x / 3 cross-multiply
3[20 - x] = 12x simplify
60 - 3x = 12x rearrange as
60 = 15x divide both sides by 15
x = 4
She should aim 4 ft to the right of "C"
EDIT TO CORRECT A PREVIOUS MISTAKE.....THANKS TO EP FOR CATCHING THIS !!!!