Surface Area of Triangular Prisms
Surface Area of Triangular Prism:
The following website has an interactive visual for the surface area formula of triangular prisms:
http://www.shodor.org/interactivate/activities/SurfaceAreaAndVolume/
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To find the surface area of a triangular prism, using a net is helpful. Draw one of the triangular
bases with the measurement of each side written down and then draw rectangles from each site.
The length of each rectangle is the length of the triangular prism.
Find the area of each piece, remembering that there are two triangles.
Add the areas together.
Example 1:
8 cm
12 cm
10 cm
12 cm
6 cm
12 cm
The area of the triangle is 6 x 8 which is 24 cm2.
2
Since there are two triangles multiply by 2:
The area of the three rectangles are: 8 cm x 12 cm =
6 cm x 12 cm =
10 cm x 12 cm =
Add these to get the surface area:
48 cm2
96 cm2
72 cm2
120 cm2
336 cm2
Surface Area Practice
Name: ____________________________
Solve each problem below!
1. Find the surface area of the triangular prism
below:
2. How much canvas would be needed for the
tent below.
Surface Area = ___________ in2
Surface Area = ___________ m2
3. A candy bar is in the shape of a triangular
prism with a height of 6 inches. Each side of the
triangle is 1 inch with a height of 0.8 in. How
much paper will be needed for the wrapping?
4. A block of cheese is in the shape of a
triangular prism shown below. What is the
minimum amount of wrapping needed to cover
the cheese?
Surface Area = ___________ in2
Surface Area = ___________ cm2
Surface Area Practice Answer Key
Name: ____________________________
Solve each problem below!
1. Find the surface area of the triangular prism
below:
2. How much canvas would be needed for the
tent below.
Area of 2 triangle bases:
Area of 2 triangle bases:
1
2
( )(2)(1.5) = 1.5 x 2 = 3
1
2
( )(3)(9) = 13.5 x 2 = 27
Area of rectangle faces:
4 x 12 = 48
7 x 12 = 84

9 x 12 = 108
Area of rectangle faces:
2x3=6

1.8 x 3 = 5.4
1.8 x 3 = 5.4
S.A. = 48 in2 + 84 in2 + 108 in2 +27 in2 = 267m2
S.A. = 3 m2 + 6 m2 + 5.4 m2 + 5.4 m2 = 19.8 m2
Surface Area = 267 in2
Surface Area = 19.8 m2
3. A candy bar is in the shape of a triangular
prism with a height of 6 inches. Each side of
the triangle is 1 inch with a height of 0.8 in.
How much paper will be needed for the
wrapping?
4. A block of cheese is in the shape of a
triangular prism shown below (height is 4 cm).
What is the minimum amount of wrapping
needed to cover the cheese?
Area of 2 triangle bases:
1
2
( )(1)(0.8) = 0.4 x 2 = 0.8
Area of rectangle faces:
1x6=6
1x6=6

1x6=6
Area of 2 triangle bases:
1
2
( )(4)(6) = 0.4 x 2 = 0.8
S.A. = 0.8 in2 + 6 in2 + 6 in2 + 6 in2 = 18.8 in2
Area of rectangle faces:
1x6=6
1x6=6

1x6=6
S.A. = 0.8 in2 + 6 in2 + 6 in2 + 6 in2 = 18.8 in2
Surface Area = ___________ cm2
Surface Area =
18.8
in
2