How many squares with side lengths of inch can fit in a square with side lengths of 1 inch?
What is the area of a square with side lengths of inch? Explain or show your reasoning.
Here is a rectangle that is inches by inches. The side length of each grid square is inch.
Show that a rectangle that is inches by inches has an area of square inches. You can use the drawing if you find it helpful.
13.3
Activity
Areas of Rectangles
Each of these multiplication expressions represents the area of a rectangle.
All regions shaded in light blue have the same area. Match each diagram to the expression that you think represents its area. Be prepared to explain your reasoning.
A
A rectangle with a horizontal dotted line about three quarters of the way down its width. The top portion is shaded blue.
B
A rectangle with a horizontal dotted line about three quarters of the way down its width and a vertical dotted line about three quarters of the way to the right of its length. The top left portion of the rectangle is shaded blue.
C
A vertically oriented rectangle shaded blue.
D
A rectangle with a vertical dotted line about three quarters of the way to the right of its length. The left portion of the rectangle is shaded blue.
Use the diagram that matches to show that the value of is .
13.4
Activity
How Many Would It Take?
Noah would like to cover a rectangular tray with rectangular tiles. The tray has a width of inches and an area of square inches.
Find the length of the tray in inches. Show your reasoning.
The tiles are inch by inch. Draw a diagram to show one way Noah could lay the tiles. Your diagram does not need to show every tile but should show known measurements.
How many tiles would Noah need to cover the tray completely, without gaps or overlaps? Explain or show your reasoning.
Student Lesson Summary
If a rectangle has side lengths units and units, the area is square units. For example, if we have a rectangle with -inch side lengths, its area is (or ) square inches.
A large square evenly divided into 4 smaller squares. The large square has bottom horizontal side length of 1 inch. Of the four smaller squares, the top left square is shaded blue. It has side lengths labeled one half inch.
This means that if we know the area and one side length of a rectangle, we can divide to find the other side length.
If one side length of a rectangle is in and its area is in2, we can write this equation to show their relationship:
Then, we can find the other side length, in inches, using division: