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Surface Area

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4. a) The cylinder has two identical circles, one at each end.What is the area of each circle?b) What is the area of the rectangle?c) The total surface area is the sum of the areas of all the shapes.What is the surface area of the glow stick? Include the units inyour final answer.Pop cans arecylinders. The world’slargest Coke can islocated in Portage laPrairie, Manitoba.Reflect on Your Findings5. a) How would you find the surface area of any right cylinder?b) What type of units do you use to measure surface area?Example 1: Determine the <strong>Surface</strong> <strong>Area</strong> of a Right Cylindera) Estimate the surface area of the can.b) What is the surface area of the can? Expressyour answer to the nearest hundredth of asquare centimetre?11 cmSolution7.5 cmThe surface area of the can is found by adding the areas of the twocircular bases and the rectangular side that surrounds them.The width, w, of the rectangle is the height of the can.The length, l, of the rectangle is equal to the circumference of the circle.a) To estimate, use approximate values: d ≈ 8 cm, w ≈ 10 cm, π ≈ 3.<strong>Area</strong> of circle = π × r 2≈ 3 × 4 × 4≈ 48There are two circles: 2 × 48 = 96The area of the two circles is approximately 96 cm 2 .<strong>Area</strong> of rectangle = l × w= (π × d) × w Replace l with the formula for the≈ 3 × 8 × 10 circumference of a circle.≈ 240The area of the rectangle is approximately 240 cm 2 .Estimated surface area = area of two circles + area of rectangle≈ 96 + 240≈ 340The estimated surface area is 340 cm 2 .r 2 meansr × rThe radius of a circleis half the diameter.LiteracyLinkcircleradiuscentrediameterThe formula for thecircumference of a circle isC = π × d or C = 2 × π × r.5.4 <strong>Surface</strong> <strong>Area</strong> of a Cylinder • MHR 25

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