To answer question 12, you first need to know the definition of a prism and a pyramid.
A pyramid is a 3-D structure with one base, whose outer faces are made of triangles, and meet at a single point at the top.
A prism is any 3-D shape with a base of any number of sides, another base with the same amount of sides, and faces joining the two together on every side of the bases.
12.
Shape A is a pyramid, because it has one base, and all the faces join together in at one point.
Shape B is a prism, because it has two bases, and faces joining every side of the bases.
Shape C is a prism.
Shape D is a pyramid.
For #13, you have to know the definition of a cube to figure out the math of how many cubes there are.
A cube is a 3-D shape with six sides, all made up of squares of the same size.
The box has a volume of 120 cubic inches, and each cube is 1 inch. Since every side of a cube is equal, a 1-inch cube is one cubic inch.
This means that a box with a volume of 120 cubic inches will fit 120 of the 1 inch cubes.
1 layer of the cubes, in the diagram, is 8 cubes by 3 cubes, or 24 cubes total.
To find the number of layers needed to fill the box, you divide 120 by 24.
120 ÷ 24 = 5
The answer to #13 is 5 layers.
