Question

What is called relation between sides and inradius of a triangle?

Answer 1

The Circle which is drawn or inscribed touching all the sides of the triangle AB BC & CA is regarded as the inradius of a Triangle. The Circle must be bisected from the centre point r equally touching all the parts of the triangle A,B & C thus making an inradius of a triangle

Answer 2

The relation is the tangency. The circle touches the sides at one point.