P.O.D. #7 basicadvanced A rotating sprinkler that sprays water at a radius of 11 ft is used to water a lawn. Find the area of the lawn that is watered. (Round to the nearest tenth.) Find the area of a circle with a radius of 12 cm. (Round to the nearest tenth.) A = πr 2 A ≈ 3.14  (12 cm) 2 A ≈ 3.14  144 cm 2 A ≈ cm 2 A ≈ cm 2 A = πr 2 A ≈ 3.14  (11 ft) 2 A ≈ 3.14  121 ft 2 A ≈ ft 2 A ≈ ft 2

Area of Composite Figures

A composite figure is made up of two or more shapes. To find the area of a composite figure, break the figure into shapes with areas you know. Then find the sum of these areas.

2 in 3 in 2 in A = ½πr 2 A ≈ ½  3.14  (1 in) 2 A ≈ ½  3.14  1 in 2 A ≈ 1.57 in 2 A = ½πr 2 A ≈ ½  3.14  (1 in) 2 A ≈ ½  3.14  1 in 2 A ≈ 1.57 in 2 A = l  w A = 2 in  3 in A = 6 in 2 Total Area = 1.57 in in in 2 = 9.14 in 2

Area = minus To find the area of some composite figures, you must subtract the area of one shape from another.

1 in 3 in Area of Square A = l  w A = 3 in  3 in A = 9 in 2 Area of Triangle A = ½  l  w A = ½  1 in  1 in A = ½ in 2 1 in Area of Blue Figure Area = 9 in 2 – ½in 2 = 8½ in 2

Whiteboard: What geometric figures make up this composite figure?

Several Possible Answers Whiteboard:

Mr. DiNardo decided to install a new floor in his living room and hallway. Below is a diagram of the space. Determine how much flooring he will need to purchase. Whiteboard: Area of Hallway: A = l  w A = 1.5 m  3.2 m A = 4.8 m 2 Area of Living Room: A = l  w A = 4.2 m  6 m A = 25.2 m 2 Total Area = 4.8 m m 2 = 30 m 2

Mrs. Sprinkle wants to build a round patio similar to the one shown in the picture. How many stone tiles will she need to purchase if each tile is 1 ft 2 ? Group Ponder / Whiteboards: 8 ft 20 ft Area of Outer Circle: A = πr 2 A ≈ 3.14  (10 ft) 2 A ≈ 3.14  100 ft 2 A ≈ 314 ft 2 Area of Inner Circle: A = πr 2 A ≈ 3.14  (4 ft) 2 A ≈ 3.14  16 ft 2 A ≈ ft 2 Total Area of Stone ≈ 314 ft 2 – ft 2 ≈ ft 2 ≈ 264 ft 2