Question

Two spheres, one with radius 7 and one with radius 4, are tangent to each other. If P is any point on one sphere and Q is any point on the other sphere, what is the maximum possible length of PQ?

Answer 1

The maximum length of PQ = The Diameter of first sphere + the diameter of second sphere = 2×7 + 2×4 = 14 + 8 = 22 ;