sphere

A solid figure that has the shape of a round ball; all points are the same distance from the center
Example:

square

A rectangle with 4 equal sides

Example:

 

square pyramid

A pyramid with a square base and four triangular faces

Example:

square unit

A unit of area with dimensions 1 unit x 1 unit

Example:

1 square unit

surface area

The sum of the areas of all the faces, or surfaces, of a solid figure
Example:
Surface Area = A + B + C + D + E + F
  = 8 + 6 + 12 + 6 + 12 + 8 = 52
  The surface area is 52 units2.

tangram

A puzzle consisting of seven polygon-shaped pieces that can be rearranged to make various figures or shapes
Example: