The surface area of a triangular prism is the sum of the areas of the two triangular bases and the three rectangular faces. Let's calculate the area of the triangular bases and the area of the rectangular faces one at a time. Then we can add them together.
Triangular Bases
Looking at the net of this solid, for now let's think only about the triangular bases.
We can see that one of the triangular bases has a base of 15 feet and a height of 8 feet. Let's find its area by substituting these values into the formula for the area of a triangle.
The area of one triangular base is 60 square feet. Because both of the triangular bases are exactly the same, we know that the area of the second triangular base is 60 square feet as well. Let's add them together!
Area of the Triangular Bases
60+60= 120ft^2
Rectangular Faces
Now let's look at the rectangular faces.
We can see that all three rectangular faces have a width of 20 feet. Also, their lengths are 8, 15, and 17 feet. Let's substitute the length and the width of each rectangle in the formula for the area of a rectangle to obtain their areas.
A=l w
Measures
Substitute
Evaluate
l= 8, w= 20
A= 8( 20)
A= 160ft^2
l= 15, w= 20
A= 15( 20)
A= 300ft^2
l= 17, w= 20
A= 17( 20)
A= 340ft^2
Surface Area of the Prism
Finally, to get the surface area of the triangular prism, we add the area of both triangular bases and the area of the three rectangular faces.
Surface Area of the Triangular Prism
120+ 160+ 300+ 340=920ft^2
