In these kind of questions what formulas i have to learn can someone please provide me with all the formulas. I face problems in solving these type of questions, in this question also i am not able to find which formula to use. Here in this question a solid toy is given to us which is in the form of a hemisphere surmounted by a right circular cone. The height of the cone is 4 cm and diameter of the base is 8 cm. We have to find the volume of the complete toy. Also if the cube circumscribes the toy, We also have to find the difference of the volumes of the cube and the toy, and lastly we have to find the total surface area of the toy.