SURFACE AREA Mrs S Brown math SURFACE AREA

SURFACE AREA Mrs. S. Brown math

SURFACE AREA Find the Area of each side and Add them together. Front: 7 x 10=70 Back: 7 x 10=70 Bottom: 4 x 7=28 Top: 4 x 7=28 Left: 4 x 10=40 Right: 4 x 10 =40 SA= 276 cm sq.

USING A NET Sometimes you can use the NET ( unfolded image of the 3 D figure) to help you find the SA: SA= 62 cm

AREA OF RIGHT TRIANGULAR PRISM (YOU NEED 2 FORMULAS FOR THE TRIANGLES AND Find the Area of each side and Add them together. RECTANGLES!!!) Front: ½(3)(4)=6 Back: ½(3)(4)=6 Bottom: 4(11)=44 Left: 3(11)=33 Top: 5(11)=55 SA= 144 cm sq.

NETS ALSO WORK WITH TRIANGULAR PRISMS! Triangles ½(10)12= 60 You would not use 13! ½(10)12= 60 It is not the base or height! Rectangles: 13 x 24 =312 10 x 24 = 240 13 x 24 = 312 SA- 984 cm sq.

SURFACE AREA OF PYRAMIDS Square Pyramid: Base: 6 x 6=36 Triangles: 4(1/2)(6) (12) = 144 SA= 180 cm squared

MORE PYRAMIDS Rectangular Pyramid: Base: (12)(8) = 96 Right and left triangles: 2(1/2)(12)(8) = 96 Front and back triangles: 2(1/2)(10)(12)= 120 SA: 312 m squared

NETS ALSO WORK WITH PYRAMIDS! Base: 6 x 6= 36 4 Triangles ½(6)5= 15 SA= 96 square units

WORD PROBLEMS!!! TRY THESE OUT! (DRAW A MODEL) Problem 1 Maddi bought a gift for her friend. She wants to place the gift in a package with the length of 9 inches, width of 12 inches, and height of 4 inches. Then she wants to wrap the gift. What is the surface area of the package? Problem 2 Acme Manufacturing Co. is making jewelry boxes that are going to be chrome plated. Acme sends its boxes off to another company to do the plating who then charges Acme. The chrome plating costs $0. 05 for every square centimeter covered in chrome. How much would it cost Acme to chrome plate a rectangular box with dimensions of 18 cm x 30 cm x 6 cm?

SOLUTIONS Problem 1 Problem 2 SA: 2(9)(12)+ 2(9)(4) +2(12)(4) SA: 2(18)(30) + 2(6)(18) +2(6)(30) SA: 216+ 72 +96 SA: 1080+ 216 + 360 SA: 384 square inches of wrapping paper will be needed to wrap the present. SA: 2016 square inches of chrome will be needed. 2016 x 0. 05= $100. 80 will be the charge

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IXL. COM PRACTICE: FF. GEOMETRIC MEASUREMENT • 16 Surface area of cubes and rectangular prisms • 18 Surface area of triangular prisms • 19 Surface area of pyramids