Question

What is the approximate base area of the resulting figure? Area of a circle: A = πr2

Answer 1

I think if you rotated that shape, the radius would be 5 in.  
Using A=pi*r^2:
A=pi*5^2
A=78.5 sqr in.

Or 79 sqr in, if you round to the nearest whole number.

Answer 2

Answer:   $78.5\ cm^2$

Step-by-step explanation:

From the given we can see that there is a  rectangle is rotated about a line bisecting its length in segment of 5 cm in each.

Since the base will be a circle, then the area of the base will be :-

$\text{Area of base}=\pi r^2\\\\\\\Rightarrow\text{Area of base}=3.14\times(5)^2\\\\\\\Rightarrow\text{Area of base}=78.5\ cm^2$

Hence, the base area of the resulting figure = $78.5\ cm^2$