1. area (geometry) the amount of space within a closed shape; the number of square units needed to cover a figure

2. base (geometry) the flat side on which a polygon sits; the flat face on which a 3- dimensional shape can rest

3. circumference the distance around a circle

4. diameter a straight line through the center of a circle; a line drawn from one side of a circle to the other that passes through the center

5. height how tall something is; the distance from the bottom to the top of something

6. length how long something is; the distance from one end to the other

7. parallelogram a shape or with four straight sides, four corners, and both sets of opposite sides parallel and the same length

8. perimeter the distance around the outside of an object or shape

9. perpendicular meeting at a right angle; at 90 degrees to something

10. pi (math) a constant with the approximate value of 3.14, written with the symbol ∏; a value that for any circle equals the circumference divided by the diameter

11. radius the distance from the center of a circle to any point on the outside edge

12. width the distance across something; the measurement of something from one side or edge to another