The formula for area of a circle is r² x π.
Since we know the diameter, we can firstly divide by 2 to find our radius.
4/2 = 2
Now that we know the radius, we can substitute it in and square the value.
(2)² x π
(4) x π
Since we're finding the area in terms of pi, we won't multiply by pi, giving us the answer of 4π.
Therefore, the area of the circle is equal to 4π.
<em>Hope this helped! :)</em>
