This is solid mensuration. I need help. Asap. Thankyou so much

12. The diameter of a sphere and the base of a cone are equal. What percentage of that diameter must the cones height be so that both volumes are equal. A. 100% B. 200% C. 50% D. 400% 13. The volume a regular pyramid whose base is a regular hexagon is 156 m3. If the altitude of the pyramid is 5 m., find the sides of the base. A. 4 m B. 8 m C. 6 m D. 3 m 14. The base of a cylinder is a hexagon inscribed in a circle. If the difference in the circumference of the circle and the perimeter of the hexagon is 4 cm., find the volume of the prism if it has an altitude of 20 cm. A. 10,367 cm3 B. 12,239 cm3 C. 10,123 cm3 D. 11,231 cm3 15. If the surface areas of two spheres are 24 cm2 and 96 cm2 respectively. Find the ratio of their volume. A. 1/4 B. 5 C. 1/8 D. 3/5 16. A conical vessel has a height of 24 cm. and a base diameter of 12 cm. It holds water to a depth of 18 cm above its vertex. Find the volume of its content. A. 381.7 cm2 B. 281.6 cm2 C. 451.2 cm2 D. 367.4 cm2 17. A rectangle ABCD which measures 18 by 24 cm is folded once, perpendicular to diagonal AC, so that the opposite vertices A and C coincide. Find the length of the fold. A. 18.5 cm B. 22.5 cm C. 21.5 cm D. 19.5 cm 18. A wooden cone is to be cut into two parts of equal volume by a plane parallel to its base. Find the ratio of the heights of the two parts. A. 2.35 B. 3.85 C.1.26 D. 1.86