Surface area of the semicircular right prism is squared

Total surface area of the semicircular right prism = 439.38 inches squared

Step-by-step explanation:

The surface area is nothing but the area of all the sides.

In the given figure, the top and bottom are the semi-circle, one rectangle and curved area.

We need to find the these areas separately and add them together we get the total surface area of the figure.

The top and bottom are the semi-circles together we get a whole circle.

Area of the top and bottom =

Given: Diameter = 18 in, Radius =

The value of π = 3.14

So, the area of the top and bottom = 3.14*9*9 = 254.34 square inches.

Now let's find the area of the rectangle.

Area of a rectangle = length *width

Area of the rectangle = 18 *4 = 72 square inches.

Now let's find the curved area.

The curved area =

Here r = 9 in and height(h) = 4 in.

Now plug in these values in the above formula, we get

The curved area = 3.14*9*4 = 113.04 square inches.

Total surface area of the semicircular right prism = 254.34 + 72 + 113.04

= 439.38 square inches.

b.an increase in a causes b to decrease