#1**+2 **

15.

Since the diameter is perpendicular to the chord AB, then it bisescts AB....thus.....AE = BE = 6

And the intersecting chord theorem says this

DE * CE = AE * BE

DE * 2 = 6 * 6

DE * 2 = 36 divide both sides by 2

DE = 18

So....the diameter = DE + CE = 18 + 2 = 20

And the radius is 1/2 of this = 10

CPhill May 8, 2018