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Perimeter, Circumference and Area http://player.discoveryeduca tion.com/?blnPreviewOnly= 1&guidAssetId=6e7387cf- 1b6c-4607-9ce3- d9d8dbc34682blnPreviewOnly= 1&guidAssetId=6e7387cf- 1b6c-4607-9ce3- d9d8dbc34682

Perimeter and Circumference Perimeter : The distance around a geometric figure. Circumference: The distance around a circle.

Perimeter To find perimeter add the lengths of all the sides. – Example: Find the perimeter of the polygon 8 in 6 in 8 in 6 in P = 8 + 8 + 6 + 6 P = 28 The perimeter is 28 in

Perimeter – Example : Find the perimeter of the triangle 12 in 16 in P = 12 + 12 + 16 P = 40 The perimeter is 40 in

Your Turn…. Find the perimeter pg. 426 #1-3 ( 3 minutes) Make sure that there are no naked numbers. 1. P = 6 + 4 + 8 P = 18m 2. P = 7 + 5 + 5 + 7 P = 24in 3. P = 8 + 8 + 8 + 8 P = 32 ft

Circumference To find the circumference multiply times diameter, where is 3.14 C = d Diameter

Definitions Diameter (d): a line that passes through the center of a circle Radius (r): half the diameter d = 20, then r = 10 r = 15, then d = 30

Circumference Example: Find the circumference Diameter = 8 in Circumference = d C = 3.14(8) C = 25.12 The circumference is 25.12 in

Circumference Example: Find the circumference radius = 10 cm Circumference = d Diameter = 2r = 2 (10) = 20 C = 3.14(20) C = 62.8 The circumference is 62.8 cm

Your Turn…. Find the circumference pg. 426 # 7-9 No naked numbers. 7. C = d 8. C = d C = 3.14(12) C = 3.14(3) C = 37.7m C = 9.4 ft 9. C = d C = 3.14 (16) C = 50. 2 in

Area of Rectangles The area of a rectangle is the product of its length and width. A = ω ω

Area of Rectangles Find the area of the rectangle 10 ft 7.5 in A = ω A = 10(7.5) A = 75 ft² The area is 75 ft²

Area of Triangles The area of a triangle is half the product of its base b and its height h. A = bh height base

Area of Triangles Example: Find the area of the triangle 6 in 5 in A = bh A = 5(6) A = 15 in ²

Area of Circles The area of a circle is the product of and the square of the circle’s radius r. A = r² radius

Area of Circles Example: Find the area of the circle r = 3 m A = r² A = 3.14(3)² A = 3.14(9) A = 28.26 m ² The area of the circle is 28.26m ²

Area of Circles d = 8 in A = r² Radius = 4 in A = 3.14(4)² A = 3.14(16) A = 50.24 in² The area of the circle is 50.24in²

Lets Review Perimeter = Sum of all sides Circumference = d Area of a Rectangle = ω Area of a Triangle = bh Area of a Circle = r²