Surface Area: Triangular Prism

2-D Shapes Area Review

Area of a Triangle = base x height / 2

Area of a Triangle = 1/2 base x height

Surface Area of a Triangular Prism

Here's a triangular prism with the dimensions:

Width of base = 6cm

length = 12 cm

height = 4 cm

By drawing the net you can see that there are 5 faces or surfaces. The two triangular bases are the same, and two of the rectangles are the same.

All triangular prisms have 2 congruent bases but the other 3 rectangles are not necessarily congruent. It will depend on the dimensions of the bases.

Rectangle A = 12 x 6 = 72cm2

Rectangle B = 12 x 5 = 60cm2

Triangle C = 1/2 x 6 x 4 = 12cm2

To find the total surface area we add all 5 surfaces together:

72 + 60 + 60 + 12 + 12 = 216cm2

The surface area = 2 times the area of the base plus the area of the other 3 sides.