National Adult Literacy Database

This video tutorial introduces the concept of perimeter, the distance around an object. The instructor notes that while any object has a perimeter, he is limiting this tutorial to triangles, circles and rectangles.

For the triangle and rectangle, he simply uses a ruler to measure the length of the sides, then adds those figures together to come up with the perimeter.

However, measuring the perimeter of a circle poses a challenge. The instructor explains that the perimeter of a circle is also called its circumference and can be calculated by multiplying its diameter by pi, usually given as 3.14.