Tangent FC and Secant EB intersect at point D, the point of tangency. What is the measure of FDB? Help is needed A.S.A.P thank you.

I suppose maybe even a formula to figure this out would be good to know.

extra information:

on the circle are two extra points... points G and A

A is on secant EB. G is a point on the circle... D and A create an arc with a measure of 270 degrees