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P ERIMETER : T HE DISTANCE AROUND A FIGURE Example What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

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Page 1: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +
Page 2: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

PERIMETER: THE DISTANCE AROUND A FIGURE

ExampleWhat is the perimeter of the figure below?12 ft

9 ft

6 ft

6 ft

18 ft

15 ft

12 ft+ 9 ft+ 6 ft+ 6 ft

+ 18 ft+ 15 ft

66 ft

Page 3: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

FORMULA: AN EQUATION THAT SHOWS HOW CERTAIN QUANTITIES ARE RELATED.Some figures have special characteristics.

For example, because the opposite sides of a rectangle have the same length, we can use a formula to find its perimeter.

PERIMETER OF A RECTANGLE: P = 2l + 2wExample: What is the perimeter of the

rectangle below?

9 m

5 m

P = 2l + 2wP = 2(9) + 2(5)P = 18 + 10P = 28

The perimeter is 28 m.

Page 4: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

AREA: THE NUMBER OF SQUARE UNITS NEEDED TO COVER ITS SURFACE.

The area of a rectangle can be found by dividing it into 1x1 squares of whatever unit we’re using

AREA OF A RECTANGLE: A = lw

5 m

4 m

Page 5: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

ExampleFind the area of the rectangle

Find the area of a rectangle with a length of 8.2 meters and a width of 2.4 meters

14 in

10 inThe area is 140 square inches

19.68 m2

Page 6: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

The opposite sides of a parallelogram also have the same length. The area of a parallelogram is closely related to the area of a rectangle.

AREA OF A PARALLELOGRAM: A = bh

height

base

Page 7: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

ExampleFind the area of the parallelogram

Find the area of a parallelogram with a height of 6 feet and a base of 8 feet

5.2 in

4 mThe area is 20.8 square meters

48 ft2

4.3 m

Page 8: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

Some math problems can be solved by using a formula. Others can be solved by a problem-solving strategy like finding a pattern (section 1) or making a model. No matter the problem, you can always use a four-step plan.1. Explore the problem2. Plan the solution3. Solve the problem4. Examine the solution

Page 9: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

Example Julia wants to paint two rectangular walls of

her bedroom. One bedroom wall is 15 feet long and 8 feet high. The other wall is 12 feet long and 8 feet high. She wants to put two coats of paint on the walls. She knows 1 gallon of paint will cover about 350 square feet of surface. Will one gallon of paint be enough? Wall one is 15 by 8 feet. What is the area? Wall two is 12 by 8 feet. What is the area? How much paint is needed to give two coats? Can Julia paint both walls twice?

120 ft2

96 ft2

432 ft2

No

Page 10: P ERIMETER : T HE DISTANCE AROUND A FIGURE  Example  What is the perimeter of the figure below? 12 ft 9 ft 6 ft 18 ft 15 ft 12 ft + 9 ft + 6 ft +

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