Question

A triangular prism has a base that is an isosceles triangle with sides ​14 cm, 14cm ​, base 9 cm ​, and height 13 cm. The height of the prism is 32 cm. What is the surface area of this​ prism?

Answer 1

Surface area of prism = 1301 cm²

Explanation:

A triangular pyramid has 3 rectangular sides and 2 triangular sides.

Now, we are told that the triangular side is isosceles.

This means that two of the rectangular sides which share a side with the equal side of the triangle are equal as well as the 2 triangular sides.

Surface area of prism = 2(area of triangular face) + 2(area of rectangle sharing one side with the equal side of the triangle) + (area of rectangle sharing side with the unequal side of the triangle).

Area of triangle = ½ × base × height

Area of triangle = ½ × 9 × 13 = 58.5 cm²

Since height of prism is 32 cm, then;

area of rectangle sharing one side with the equal side of the triangle = 32 × 14 = 448 cm²

area of rectangle sharing side with the unequal side of the triangle = 32 × 9 = 288 cm²

Thus;

Surface area of prism = 2(58.5) + 2(448) + 288

Surface area of prism = 1301 cm²