04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

1-3: Using Formulas1-3: Using Formulas

Expectation:Expectation:You will be able to use the formulas for area and perimeter You will be able to use the formulas for area and perimeter of a rectangle to calculate (with correct units) the area and of a rectangle to calculate (with correct units) the area and

perimeter of various rectangles.perimeter of various rectangles.

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

A Problem Solving PlanA Problem Solving Plan

1. Carefully read the problem.

- Make sure you understand what you are trying to determine.

2. Plan your solution.

- What formula or equation will you use?

3. Solve the formula or equation.

4. Answer the question.

5. Make sure your answer is reasonable.

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

Area Formula for a RectangleArea Formula for a Rectangle

If the area, length and width of a rectangle are represented by A, l and w respectively, then A = _______.

Remember area is always measured in square units.

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

A rectangle has length of 25 inches and width of 1 foot. What is the area of the rectangle?

Give the dimensions of 3 rectangles whose Give the dimensions of 3 rectangles whose areas are all 48 cmareas are all 48 cm22..

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

Perimeter of a RectanglePerimeter of a Rectangle

If the perimeter, length and width of a rectangle are represented by P, l and w respectively, then

P = __________.

Remember perimeter is always measured in plain (linear) units.

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

The perimeter of a rectangle is 102 inches. If the width of the rectangle is 21 inches,, what is the length of the rectangle?

The perimeter of a rectangle is 96 inches. If the length of the rectangle is 3 times its width, what is the sum of the length and width of the rectangle?

A.12

B.24

C.36

D.48

E.Cannot tell from the given information

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

The length of a rectangle is 3 more than twice the width and the area is 69 square meters. Write expressions for the perimeter and area of the rectangle.

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

Work in PairsWork in Pairs

1. Each pair will be assigned one of the following numbers to use as the perimeter of a rectangle. 24, 32, 40, 48, 56, 64

2. For your perimeter, determine the length and width of the rectangle that will give you the largest area (you should have at least three rectangles that fit your perimeter).

3. Be prepared to discuss your solution.

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

Anything Worth Noting?Anything Worth Noting?

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

Another OneAnother One

1. This time you will use a number below as the area of your rectangle.25, 49, 81, 121, 169, 225

2. Determine the length and width of the rectangle that gives you the smallest perimeter (again, you should have 3 rectangles that fit your area).

3. Be prepared to discuss your solution.

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

Anything Worth Noting Here?Anything Worth Noting Here?

A rectangular parking lot that is 3 feet longer than it is wide has an area of 550 square feet. How many feet long is the parking lot?

A.19

B.20

C.22

D.25

E.28

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

04/21/2304/21/23 1-3: Using Formulas1-3: Using Formulas

AssignmentAssignment

Pages 23 – 24,

# 15, 21, 25, 31, 41 and 43