1. How do you calculate the area of squares and rectangles?
8.3
ESSENTIAL QUESTION
How do you calculate the area of squares and rectangles?

2. Vocabulary
Area: The amount of surface covered by a figure

4. Find the area of the square.
Example 1
Find the Area of a Square
Find the area of the square.
SOLUTION
Use the formula for the area of a square and substitute
9 for s.
A = s2
Formula for the area of a square
= 92
Substitute 9 for s.
= 81
Simplify.
The area of the square is 81 square feet.
ANSWER

6. Find the area of the rectangular pool.
Example 2
Find the Area of a Rectangle
Find the area of the rectangular pool.
Use the formula for the area of a rectangle. Substitute 24 for b and 16 for h.
SOLUTION
A = bh
Formula for the area of a rectangle
= 24 · 16
Substitute 24 for b and 16 for h.
= 384
Multiply.
The area of the pool is 384 square feet.
ANSWER

7. The rectangle has an area of 54 square inches. Find its height.
Example 3
Find the Height of a Rectangle
The rectangle has an area of 54 square inches. Find its height.
Use the formula for the area of a rectangle and substitute 54 for A and 9 for b.
SOLUTION
A = bh
Formula for the area of a rectangle
54 = 9h
Substitute 54 for A and 9 for b.
6 = h
Divide each side by 9.
The height of the rectangle is 6 inches.
ANSWER

8. Find the dimensions of rectangles A and B.
Example 4
Divide a Complex Polygon into Rectangles
Find the dimensions of rectangles A and B. 8

9. Find the dimensions of rectangles A and B.
Example 4
Divide a Complex Polygon into Rectangles
Find the dimensions of rectangles A and B.
SOLUTION
Rectangle A
The base is 5 units.
Because rectangle B is 2 units taller than
rectangle A, the height of rectangle A is
7 – 2 = 5 units.
Rectangle B
The height is 7 units.
The base of rectangle B is the total of
both bases minus the base of rectangle A,
or 9 – 5 = 4 units. 9

10. Area = Area of A + Area of B
Area = 53 units squared

11. Find the area of the polygon made up of rectangles.
Checkpoint
Polygons Made Up of Rectangles
Find the area of the polygon made up of rectangles. 5. 11

12. Find the area of the polygon made up of rectangles.
Checkpoint
Polygons Made Up of Rectangles
Find the area of the polygon made up of rectangles. 6.
ANSWER
54 m2 12

13. Worksheet 8.3A