#1**+1 **

I'll give you a few hints:

1) Draw an altitude h from D to a point F on line segment AM. h = 2r

2) Find the lengths of lines AF and FM

3) Use the Pythagorean theorem to find the length of DM.

(btw., ignore those suggested answers; the length of DM is totally different from those numbers.)

Dragan Jul 17, 2020