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Surface Area

Surface Area. Definition. Surface Area – is the total number of unit squares used to cover a 3-D surface. Find the SA of a Rectangular Solid. A rectangular solid has 6 faces. They are:. Front. Top Bottom Front Back Right Side Left Side. Top. Right Side.

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Surface Area

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  1. Surface Area

  2. Definition • Surface Area – is the total number of unit squares used to cover a 3-D surface.

  3. Find the SA of a Rectangular Solid A rectangular solid has 6 faces. They are: Front • Top • Bottom • Front • Back • Right Side • Left Side Top Right Side We can only see 3 faces at any one time. Which of the 6 sides are the same? • Top and Bottom • Front and Back • Right Side and Left Side

  4. Surface Area Front: 5cm x 4cm = 20cm2 Back: 5cm x 4cm = 20cm2 Right Side: 2cm x 4cm = 8cm2 Left Side: 2cm x 4cm = 8cm2 Top: 5cm x 2cm = 10cm2 Bottom: 5cm x 2cm = 10cm2 Add up all the sides up: 76 cm2

  5. Surface Area of a Rectangular Solid We know that Each face is a rectangle. and the Formula for finding the area of a rectangle is: A = lw Front Top Right Side Steps: Find: Area of Top Area of Front Area of Right Side Find the sum of the areas Multiply the sum by 2. The answer you get is the surface area of the rectangular solid.

  6. Find the Surface Area of the following: Find the Area of each face: 12 m Top: 12 m x 5 m = 60 m2 Top and Bottom: 2 x 60= 120 m2 Top 5 m Top Front: 12 m x 8 m = 96 m2 Front and Back: 2x 96= 192 m2 Front Right Side 8 m 8 m Front 5 m 12 m 12 m Right Side Right = 8 m x 5 m = 40 m2 Right and Left: 2x40= 80 m2 Sum = 120 m2 + 192 m2 + 80 m2 = 392 m2 8 m 5 m The surface area = 392 m2

  7. Find the Surface Area Using the FORMULA Rectangular Prism SA = 2(lw) + 2(wh) + 2(lh) LOW WHO LOH PLUG INTO FORMULA 2(6x4) + 2(4x14) + 2(6x14) 2(24) + 2(56) + 2(84) 48 + 112 + 168 = H= 14 cm W= 4 cm L= 6 cm The surface area of this rectangular solid is 328 cm2.

  8. Nets • A net is all the surfaces of a rectangular solid laid out flat. Back 8 cm Top Left Side Top Right Side 5 cm 8 cm Right Side Front 8 cm Front 8 cm 5 cm 10 cm Bottom 5 cm 10 cm

  9. Find the Surface Area using nets. 80 Top Back 8 cm Right Side Front 40 50 40 8 cm Left Side Top Right Side 5 cm 5 cm 8 cm 80 10 cm Front 8 cm Each surface is a rectangle. A = lw 50 5 cm Bottom Find the area of each surface. Which surfaces are the same? Find the Total Surface Area. 10 cm What is the Surface Area of the Rectangular solid? 340 cm2

  10. Surface of a Cube: 6 a 2 • How many sides are there? 6 sides • Area of one side is a x a = a2 • 6 (32) = 6(9) = 54cm2 a Area of one side is 3 x 3 = 9 There are 6 sides: 6 x 9 = 54 3cm

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