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Surface AreaUsed with 3-D figuresIs the sum of the areas of ALL its surfacesThe total area of its net
Units are squared Imagine wrapping a present, you
cover all of the surfaces. This would also give you the surface area!
ExampleFind the surface area of the following prism:
SA =2(8)5 + 2(8)4 + 2(5)4SA = 80 + 64 + 40SA = 184 cm2
CylindersFind the surface area of the following cylinder:
SA = 2(п)3(6) + 2(п)32
SA = 36п + 18пSA = 54п units2
You Try!Find the surface area of the following triangular prism:
SA = 2(½)5(12) + (12+5+13)7SA =60+ (30)7SA = 60 + 210SA = 270 units2
How Do You Find Surface Area?You can use a formula –
Cubes & Rectangular Prisms:SA = 2lw + 2lh + 2wh
Cylinders:SA = 2пrh + 2(пr2)
Triangular Prisms:SA = 2(½bh) + (perimeter)h
Perimeter is of one base face
Try This!Find the surface area of the following prism:
SA = 2lw + 2lh + 2whSA =2(7)2 + 2(7)4 + 2(2)4SA = 28 + 56 + 16SA = 100 cm2
PrcaticeFind the surface area of the following triangular prism:
SA = 2(½bh) + (perimeter)hSA =2(½)7(15) + (7+25+24)15SA = 105 + (56)15SA = 105 + 840SA = 945 units2