thus, we see that the areas of the internal triangles are directly proportional
to the barycentric coordinates of P.
This is quite a useful relationship and can be used to resolve various geometric
problems. For example, let’s use it to find the radius and centre of the
inscribed circle for a triangle. We could approach this problem using classical
Euclidean geometry, but barycentric coordinates provide a powerful analytical
tool for resolving the problem very quickly.
Consider triangle ΔABC with sides a, b, and c as shown in Figure 11.17.
The point P is the centre of the inscribed circle with radius R. From our
knowledge of barycentric coordinates we know that