Question

The diameter of a circle is 4 kilometers. What is the area?
d=4km
Give the exact answer in simplest form
_______ Square Kilometers

Answer 1

To find the area of a circle, we use the formula:

\[
A = \pi r^2
\]

where \( r \) is the radius of the circle. The radius is half of the diameter. Given that the diameter \( d = 4 \) km, we can calculate the radius as follows:

\[
r = \frac{d}{2} = \frac{4 \text{ km}}{2} = 2 \text{ km}
\]

Now we can substitute the radius into the area formula:

\[
A = \pi (2 \text{ km})^2 = \pi \cdot 4 \text{ km}^2 = 4\pi \text{ km}^2
\]

So the exact area of the circle in simplest form is:

\[
\boxed{4\pi} \text{ Square Kilometers}
\]