Unit 5 PowerPoint Presentation Victoria Bell-Netzelman July 2011 – EDUC 5131

Learning How to Use the Formulas for Area Circle Rectangle Square Triangle

Area of a Circle Area =  r 2 r  3.14 r = radius

Area of a Square Area = s 2 s ss s s = length of side

Area of a Triangle Area = ½ bh h b h = height of triangle b = length of base

Area of a Rectangle Area = lw l w l = length of rectangle w = width of rectangle

Circle Rectangle Square Triangle Match the Shape with it’s Formula Area = lw Area = ½ bh Area = s 2 Area =  r 2

Calculate the area of the Circle r = 5 ft Area =  r 2 Area =  (5) 2 Area =  (25) Area = 78.5 ft 2

Calculate the area of the Square Area = s 2 Area = (4) 2 Area = 16 ft 2 s ss S = 4 ft

Calculate the area of the Triangle Area = ½ bh Area = ½ (6)(3) Area = ½ (18) Area = 9 ft 2 h = 3 ft b = 6 ft

Calculate the area of the Rectangle Area = lw Area = (6)(2) Area = 12 ft 2 l = 6 ft w = 2 ft

Group 1 Word Problem A fence surrounds a circular field that has a radius of 15 feet. What is the area of the field inside the fence?

Group 2 Word Problem A room is 12 feet by 12 feet. What is the area of the room?

Group 3 Word Problem A pond is in the shape of a triangle that has a base of 30 feet and a height of 40 feet. What is the area of the surface of the pond?

Group 4 Word Problem A garden has a fence that is 7 feet long and 6 feet wide. What is the area of the garden?

Group 1 Word Problem A fence surrounds a circular field that has a radius of 15 feet. What is the area of the field inside the fence? Solution: r = 15 ft Area =  r 2 Area =  (15) 2 Area =  (225) Area = ft 2

Group 2 Word Problem Solution: Area = s 2 Area = (12) 2 Area = 144 ft 2 A room is 12 feet by 12 feet. What is the area of the room? S = 12 ft S SS

Group 3 Word Problem Solution: Area = ½ bh Area = ½ (30)(40) Area = ½ (1200) Area = 600 ft 2 A pond is in the shape of a triangle that has a base of 30 feet and a height of 40 feet. What is the area of the surface of the pond? h = 40 ft b = 30 ft

Group 4 Word Problem Solution: Area = lw Area = (7)(6) Area = 42 ft 2 A garden has a fence that is 7 feet long and 6 feet wide. What is the area of the garden? l = 7 ft w = 6 ft

Homework Assignment 1.Go home and pick one room in your house to re- carpet. 2.Measure the rooms dimensions and use a formula from this lesson to determine the amount of carpet needed. 3.Go to Lowe’s website and use the square feet that you calculated to find out how much it will cost to purchase the carpet you want to buy.Lowe’s website 4.Click on the link below and study the calculations for calculating area for other shapes. We will discuss these other shapes tomorrow. Area Calculation Tool