Circles with radii 1 and 2 are inscribed in triangle ABC, as shown. Find the area of triangle ABC.
Draw perpendiculars from the centers of both circles to a side of the triangle
Using similar triangles we have that
(h - 5) / 1 = ( h - 2) /2
2 (h - 5) = 1 ( h -2)
2h -10 = h - 2
h = 8
Let the center of the top circle = D the apex = A and the point where the radius of this circle meets the side of the triangle, E....angle ACB = 90.....and AD = 3 DE = 1
So
AE = sqrt ( AD^2 + DE^2) = sqrt( 3^2- 1^2) = sqrt(8)
tan DAE = DE/ AE = 1/sqrt (8)
So
tan DAE = (base/2) / height
1/sqrt (8) =base/2 * 8
8/sqrt (8) = base/2 =sqrt (8)
So [ ABC ] = ( base / 2) * height = 8 sqrt (8)