The radius of circle o is 18, and oc = 13. find ab. round to the nearest tenth, if necessary. (the figure is not drawn to scale.) a. 12.4 b. 3.8 c. 24.9 d. 44.4

We are asked to solve for the length AB of the given circle with center O.
The angle of OCB is 90°, therefore, we can apply SOH CAH TOA and Pythagorean theorem in the problem.

OB² = OC² + CB² where OB is the radius which means its length is equal to 18 units. 
OB = 18 units
OC = 13 units

18² = 13² + CB²
CB = 12.45 units

AB is twice of CB length, therefore we have:
AB = 12.45 * 2
AB = 24.9 units

The answer is the letter "C".