Answer:
9 1/3
Step-by-step explanation:
SOH CAH TOA, to remember how trig functions fit on triangle
find A in triangle ABE
to find that angle use Cos(Ф) = Adj / Hyp b/c we know the adj and the hyp in that triangle next to that angle A in ABE triangle
Ф = arccos(7/9) = 38.942°
that triangle is the same one as what make a 90 at D but outside of our parallelogram so subtract that angle from 90 for D inside our parallelogram... it's 51.058° , D on the inside of our shape.
so now we have the hyp and angle of a right triangle and can use sin to find side a f
sin(51.058) = opp / hyp
12* sin(51.058) = 9.33339 ( i'm wondering if I've got a rounding error and it's really 9 1/3 it's very very close to that if not. )
side a f 9 1/3
if you don't follow all of my logic in finding that just ask :)
