EMS Homework Help

Area, Circumference, and Perimeter

Overview: In this lesson you will learn how to find the area of shapes, the circumference of shapes and the perimeter of shapes.

How to Find the Area of Shapes

The area of a shape is the space inside of the shape. To find area you use the method length times width equals area or L•W=A
Definition: the inside space of a two-dimensional figure.

What an area problem looks like

Picture
Area=Length•Width. In this problem the numbers are 53 inches and 21 inches. You should fill in the variable letters (L,W). So if your variable problem was; L•W=? you will put the 53 in the length spot and the 21 in the width spot. 53•21=113 inches.

How to Find the circumference

The circumference is the distance around the circle
Definition:the outer boundary, especially of a circular area; perimeter:

How to Find the Perimeter of Shapes

The perimeter of a shape is the distance around the shape. To find area you use the method L+W+L+W=P.
Definition:the border or outer boundary of a two-dimensional figure.
Picture
Pi equals 3.14 or 22 sevenths. It will usually be referred to as 3.14

What a perimeter problem looks like

Picture
Perimeter=L+W+L+W
In this problem the numbers are: 50,73,50, and 73. You need to fill in the variable numbers. (L,W,L, and W). The variable problem was L+W+L+W=? You will put the 50's in the L spots and the 73's in the W spot. 50+73+50+73=246 inches.

What a circumference problem looks like

Picture
There are 2 different ways to find the circumference both shown on the left. The first is pi (3.14) times the diameter. The second one is 2 times pi (3.14) times radius.
Remember, the radius is half the size of the diameter and the diameter is 2 times larger than the radius.

Diameter and Radius example problems

Picture
As you may have read above, there are 2 ways to find the circumference. pi times the diameter and 2 times pi time the radius.
Option number one example: 3.14•16 (diameter)
Option number two example:2•3.14•8 (radius)