The length of the radius r of the given triangle is; B: 10 units
Pythagoras Theorem
We can see a circle and a triangle from the image given. Now, the one that we are most concerned with is the Triangle since that is what we can use to determine the radius of the circle of which it is a tangent.
Now, we see that triangle JKL is a right angle triangle.
Thus using Pythagoras theorem;
r² + 24² = (r + 16)²
r² + 576 = r² + 32r + 256
r² will cancel out to give;
576 - 256 = 32r
320 = 32r
r = 320/32
r = 10 units
Read more about Pythagoras theorem at; https://brainly.com/question/1783328