PLS HELP ME
How do you find the radius???

r = 15

Step-by-step explanation:

Using Pythagoras' identity in the right triangle OAB

with OM and OB the radii r of the circle

OA² = OB² + AB²

(r + 10)² = r² + 20² ← expand left side using FOIL

r² + 20r + 100 = r² + 400 ( subtract r² from both sides )

20r + 100 = 400 ( subtract 100 from both sides )

20r = 300 ( divide both sides by 20 )

r = 15

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right