Here, we want to use the given information to calculate the lateral and the total surface area
To find the lateral area, we have to calculate the perimeter of the base and multiply this by the height of the triangular prism
Now, we will make the shape lie on its side
This mean the triangles will represent the base
Mathematically, the perimeter of a triangle is the sum of its side
We need the last side of the triangle
We can get this by the use of Pythagoras' theorem
As we can see, the side measure 5 is the hypotenuse as it faces the right angle
The square of the hypotenuse equals the sum of the squares of the two other sides
3,4 and 5 are a Pythagorean triple
This means that, the measure 3 is the last side of the triangle
So the perimeter is;
The height is the measure 8 inches
Thus, the lateral area is;
Now, we want the total surface area, but firstly, we need the area of the base
The area of the base is the area of the triangle
two times this is 12 in^2
The total suface area is thus;