AB is a tangent to the circle
Solution:
Given data:
AB = 21, AC = 20 and BC = 29
To prove BC² = AB² + AC²:
BC² = 29²
BC² = 841
AB² + AC² = 21² + 20²
= 441 + 400
AB² + AC² = 841
So, BC² = AB² + AC².
Therefore by Pythagoras theorem, angle A is right angle.
Therefore AB is a tangent to the circle.
