5
5
The formula for the area of a circle is:

Area=π(Radius)2\text{Area} = \pi * \text{(Radius)}^{2}

The radius is the distance from the center of the circle to the edge:
radius
In this problem we have been given the diameter of the circle. The diameter is the distance from one edge of the circle to the opposite edge:
diameter
The diameter of a circle is always twice as long as the radius
In this problem, the diameter of the circle is 55
5
Radius=Diameter2\text{Radius} = \dfrac{\text{Diameter}}{\text{2}}
Radius=52\text{Radius} = \dfrac{5}{2}
Radius=2.5\text{Radius} = 2.5
2.5
To find the area of the circle, square the radius:
(2.5)2=6.25\left(2.5\right)^{2} = 6.25
Now multiply by π\pi. The number π\pi is approximately equal to 3.14.
Area=π(Radius)2\text{Area} = \pi * \text{(Radius)}^{2}
Area=3.146.25\text{Area} = 3.14 * 6.25
Area=19.63\text{Area} = 19.63