The Deweys' car gets 20 miles per gallon (mpg).

The Stones' car gets 30 miles per gallon (mpg).

The Webers' car gets 15 miles per gallon (mpg).

The Golds' car gets 24 miles per gallon (mpg).

Four families traveled from different places to vacation together at a lake. The Deweys drove 210 miles. The Webers drove 50 miles less than the Deweys drove. The Golds drove 100 miles more than the Webers drove. The Stones drove 110 miles more than the Webers drove. The drawing shows the gas mileage for each family's car. How many gallons of gas did each family use to get to the lake? (Round answers to the nearest tenth.)

Trip to the Lake

• The Deweys used 10.5 gallons of gas.The Webers used 10.7 gallons of gas.The Golds used 10.8 gallons of gas.The Stones used 9 gallons of gas.

Geometry: Perimeter and Area

Lesson 6-8

Find the perimeter and area of figures

Perimeter

• The distance around a figure.

• One way to find the perimeter of a figure is to add the length of all the sides.

• When finding the perimeter of a rectangle we use a common formula.

Perimeter of a Rectangle

• P= 2L + 2W

L

W

Perimeter of a Rectangle

• P= 2L + 2W

• 2(15) + 2(4)

• 30 + 8

• P = 38cmL= 15 cm

W= 4cm

Your Turn

18 ft

2 ft

•P= 2L + 2W

•2(18) + 2(2)

•36 + 4

•P = 40 ft

Find the Perimeter of an Irregular Figure

2.4 cm

1.6 cm

2.4 cm•Add the length of the sides:

•2.4 + 2.4 + 1.6 =

•6.4 cm

Find the Perimeter of a Square

• P = 4s

• S = side of the square

• P = 4(12)

• P= 48 in

12 in

Area

• The measure of the surface enclosed by the figure.

• To find the area of a rectangle we use this common formula.

• A = L x W

Find the Area of a Rectangle

• A = L x W

L

W

Find the Area of a Rectangle

• A = L x W

• A = 18 x 23

• A = 414 ft L =18ft

W= 23 ft

2

Units for area are always squared!!!

Find the area of a Square

• Formula: A = S

• Which means to multiply s x s

• A = 11

• A = 11 x 11

• A = 121 in

2

11 in

2

2

Let’s Practice

• Lesson 6-8 Page 579

• # 1-3 and 4-12 evens

Homework

• Lesson 6-8 # 2-14 evens

• Make sure you read the directions, for some questions you should find area and perimeter. You should have two answers for some questions!