Can someone explain how to solve this and give me the answer plz

To prove that angle def = angle dgf by sas, what additional information is needed? def congruent to dgf dfe congruent to dfg de congruent to dg dg congruent to gf

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.

Which function has an inverse that is also a function? a. g(x) = 2x-3 b. k(x) = -9x2 c. f(x) |x+2| d. w(x) = -20