A pot is made from a hollow sphere of inner radius 20 cm by cutting its upper portion horizontally. The height of the pot is 30 cm. What is the inner radius of the circular opening of the pot so formed?

Sphere radius R = 20. Pot height 30 cm means depth from top of sphere where cut is made. From center, the cut is at vertical distance d from center such that R + d... wait. The sphere has total diameter 40 cm. If height of pot is 30, cut is at 30 cm from bottom, i.e., 10 cm above center. Radius of circular opening: r² + 10² = 20², r² = 400 - 100 = 300, r = 10√3 cm.