Question

Determine if line AB is tangent to the circle. Type

Answer 1

Answer:

If AB is a tangent to the circle, the triangle ABO is right angled, as the angle where a tangent meets the circumference is always 90 degrees.

We also know that Pythogoras' theorem only holds for right angled triangles.

The hypotenuse is 12 + 8 as 12 is the radius so is 20.

16^2+12^2 = 256 + 144 = 400 = 20^2 so AB must be tangent.