1. CHAPTER 3
SECTION 7

2. Using Formulas Goal: Solve problems by using formulas, solve
problems involving the perimeters and
areas of rectangles.
A formula is an equation that shows a relationship among certain quantities.
Examples:
1. D = RT 2. A = BH 3. A = lw 4. P = 2l + 2w

3. Examples using the Distance Formula
What is the rate in miles per hour of a dolphin that travels 120 miles in 4 hours?
How long will it take you to drive 480 miles if you drive 60mph?
If you drive 55mph for 7 hours how far have you traveled?

4. Area of a Rectangle Formula
What is the area of a rectangle with length of 5ft and a width of 3ft? 2.
6ft
9ft 3.
8cm
13cm

5. Perimeter of a Rectangle Formula
1. What is the perimeter of a rectangle with a length of 5m and a width of 7m? 2.
8in
13in 3.
14ft
20ft

6. Given the area find the missing dimension1.
A = 42in2 w
6in 2.
A = 84cm2
7cm l

7. Given the perimeter find the missing dimension1. w
P = 38in
9in 2.
4cm
P = 22cm l

8. Word Problems:
1. The perimeter of a rectangle is 30ft. Its width is 5cm, what is its length?
2. The area of a rectangle is 63in2. Its length is 9in, what is its width?

9. PRACTICE
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