Question

The diameter of Z is 5 in. What is its area in terms of pi?
A. 2.5in.2
B. 5in.2
C. 6.25in.2
D. 25in.2

Answer 1

we are given the diameter of the circle, I assume. In this case, the formula of the area of the circle is expressed as A = pi d^2/4. where pi is a constant. The only option taht makes sense here is C. 6.25 in2. This should have the constant pi on it. 

Answer 2

we know that

the area of the circle is equal to

$A=\pi r^{2}$

where

r is the radius of the circle

In this problem we have

$Diameter=5\ in\\r=Diameter/2\\r=5/2\\r=2.5\ in$

substitute the value of r in the area's formula

$A=\pi*2.5^{2}$

$A=6.25\pi\ in^{2}$

therefore

the answer is

$6.25\pi\ in^{2}$