A sphere has a radius of 10 cm. A right circular cone has a height of 10 cm and base diameter of 10 cm. The sphere and the cone stand on a horizontal surface. If a horizontal plane cuts both the sphere and the cone, the cross-sections will both be circles.
Find the height of the horizontal plane (from the bottom) (in cm) that gives circular cross-sections of the sphere and cone of equal area.
I agree. Unless I have misunderstood his solution, Charlie has assumed a cone radius of 10, rather than a cone diameter of 10 (with a radius of 5). Using Charlie's method, but the correct radius, his answer agrees with yours.
re(2): solution
