Question

A right prism has height 7½ and triangular bases with sides of length 5, 12, and 13 What is the: Total Surface Area of the Prism

Answer 1

Given:

A right prism has height 7½ and triangular bases with sides of length 5, 12, and 13.

To find:

The total surface area of the prism.

Solution:

We have,

Height of prism = 7½ = 7.5

Sides of triangular base are 5, 12, 13. These sides of Pythagorean triplets because

$5^2+12^2=13^2$

$25+144=169$

$169=169$

So, the base of the prism is a right triangle.

Area of a triangle is

$Area=\dfrac{1}{2}\times base \times height$

$A_1=\dfrac{1}{2}\times 5\times 12$

$A_1=30$

The area of the base is equal to the area of the top, i.e., $A_2=30$ sq units.

Perimeter of the base is

$P=5+12+13$

$P=30$

The curved surface area of the prism is

$CSA=\text{Perimeter of the base}\times \text{Height of the prism}$

$CSA=30\times 7.5$

$CSA=225$

Now, the total area of the prism is

$A=A_1+A_2+CSA$

$A=30+30+225$

$A=285$

Therefore, the total surface area of the triangular prism is 285 square units.