Question

How would I determine whether AB is tangent to oc?
The o is a circle dot

Answer 1

see explanation

Explanation:

If AB is a tangent then ∠ ABC = 90° and Δ ABC is right

Using the converse of Pythagoras' identity

If the square of the longest side is equal to the sum of the squares on the other 2 sides.

15 is the longest side and 15² = 225

9² + 12² = 81 + 144 = 225

Thus Δ ABC is a right triangle at B

Thus AB is a tangent to the circle at B