Three circles packed inside a triangle such that each is tangent to the other two and to two sides of the triangle are known as Malfatti circles. The Malfatti configuration appears on the cover of Martin. The positions and radii of the Malfatti circles can be found by labeling sides and distances as illustrated above. The length of the projection of the line connecting circles Γ_1 and Γ_2 onto side A B can be found from the diagram at right to be d_12 | = | sqrt((r_1 + r_2)^2 - (r_2 - r_1)^2) | = | 2sqrt(r_1 r_2).