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Preview. Warm Up. California Standards. Lesson Presentation. Warm Up 1. A rectangular prism is 0.6 m by 0.4 m by 1.0 m. What is the surface area? 2. A cylindrical can has a diameter of 14 cm and a height of 20 cm. What is the surface area to the nearest tenth? Use 3.14 for . 2.48 m 2.
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Preview Warm Up California Standards Lesson Presentation
Warm Up 1. A rectangular prism is 0.6 m by 0.4 m by 1.0 m. What is the surface area? 2. A cylindrical can has a diameter of 14 cm and a height of 20 cm. What is the surface area to the nearest tenth? Use 3.14 for . 2.48 m2 1186.9 cm2
California Standards Extension of MG2.1 Use formulas routinely for finding the perimeter and area of basic two-dimensional figures and the surface area andvolume of basic three-dimensional figures, including rectangles, parallelograms, trapezoids, squares, triangles, circles,prisms, and cylinders.
Vocabulary slant height regular pyramid right cone
The slant height of a pyramid or cone is measured along its lateral surface. Regular Pyramid Right cone The base of a regular pyramid is a regular polygon, and the lateral faces are all congruent. In a right cone, a line perpendicular to the base through the vertex passes through the center of the base.
1 2 = (2.4 • 2.4) + (9.6)(3) Additional Example 1: Finding Surface Area Find the surface area of the figure to the nearest tenth. Use 3.14 for p. 1 2 S = B + Pl = 20.16 ft2
1 2 = (3 • 3) + (12)(5) CheckIt Out! Example 1 Find the surface area of each figure to the nearest tenth. Use 3.14 for p. 5 m 1 2 A. S = B + Pl 3 m = 39 m2 3 m B. S = pr2 + prl 18 ft = p(72) + p(7)(18) 7 ft = 175p 549.5 ft2
Additional Example 2: Exploring the Effects of Changing Dimensions A cone has diameter 8 in. and slant height 3 in. Explain whether tripling only the slant height would have the same effect on the surface area as tripling only the radius. Use 3.14 for p. They would not have the same effect. Tripling the radius would increase the surface area more than tripling the slant height.
CheckIt Out! Example 2 A cone has diameter 9 in. and a slant height 2 in. Explain whether tripling only the slant height would have the same effect on the surface area as tripling only the radius. Use the 3.14 for p. S = pr2 + pr(3l) S = pr2 + prl S = p(3r)2 + p(3r)l = p(4.5)2 + p(4.5)(2) = p(4.5)2 + p(4.5)(6) = p(13.5)2 + p(13.5)(2) = 29.25p in2 91.8 in2 = 47.25p in2 148.4 in2 = 209.25p in2 657.0 in2 They would not have the same effect. Tripling the radius would increase the surface area more than tripling the height.
Additional Example 3: Application The upper portion of an hourglass is approximately an inverted cone with the given dimensions. What is the lateral surface area of the upper portion of the hourglass? a2 + b2 = l2 Pythagorean Theorem 102 + 242 = l2 l = 26 Lateral surface area L = prl =p(10)(26)816.8 mm2
CheckIt Out! Example 3 A large road construction cone is almost a full cone. With the given dimensions, what is the lateral surface area of the cone? a2 + b2 = l2 Pythagorean Theorem 92 + 122 = l2 l = 15 12 in. 9 in. Lateral surface area L = prl =p(9)(15)424.1 in2
Lesson Quiz: Part I Find the surface area of each figure to the nearest tenth. Use 3.14 for p. 1. the triangular pyramid 2. the cone 6.2 m2 175.8 in2
Lesson Quiz: Part II 3. Tell whether doubling the dimensions of a cone will double the surface area. It will more than double the surface area because you square the radius to find the area of the base.