4

Part of 2021 Adygea Teachers' Geometry Olympiad

Problems(1)

4 spheres, each tangent to other 3 (2021 Adygea Teachers' Geometry Olympiad p4)

Source:

Two identical balls of radius

\sqrt{15}

and two identical balls of a smaller radius are located on a plane so that each ball touches the other three. Find the area of the surface

S

of the ball with the smaller radius.

geometry3D geometryspheretangent