Video and Examples
Area is the number unit squares that fit inside a figure. A unit square is a square that is one unit long by one unit wide where the unit of length can be millimeters, inches, feet, miles, etc. To find the area of a rectangle, you need to imagine it being cut into its unit squares, and then count the number of unit squares inside that rectangle. 
In this 4by6 rectangle it is pretty easy to see that the rectangle can be cut into 24 unit squares. If each unit square is 1 cmby1 cm, then we say the area of the rectangle is 24 square centimeters. This is often written as 24 cm^{2}.
Rather than counting all the unit squares in the 4by6 rectangle, a quicker method for finding the number of unit squares in a rectangle is to multiply the length of the base by the height.
6 cm • 4 cm = 24 cm^{2}
What is the area of a rectangle with a base of 5 units and a height of 8 units?
As we have already learned, you need to imagine the rectangle cut into its unit square and then counting the unit squares. A shortcut is to multiply the base by height.
Area = base • height
Area = bh
Area =(5 units)(8 units) = 40 ^{2}
Area of other shapes
Finding the area of other shapes is essentially the same as finding the area of a rectangle. You need to count the number of unit squares inside the figure. This is the case whether the figure is a rectangle, triangle, trapezoid, or circle.
For each figure, there is a formula for finding the number of unit squares rather than having to count the unit squares onebyone. These formulas will be explain in other parts of this website.
Directions:
• Find a formula for calculating the perimeter of the rectangle. • Find a formula for calculating the area of the rectangle.

SelfCheck
Question 1 Find the area of this rectangle.

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Question 2 Find the area of this rectangle.

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Question 3 A rectangle with a base of 6 centimeters has an area of . What is the height of this rectangle?

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