Lucas R. answered • 01/13/21
Middle, High School, and early College Tutor for Math and Music
Here we are asked to find the area of a circle.
The typical formula to find the area of a circle is this:
A = π r2 where A = the area of the circle, r = the radius of the circle, and π = pi, the math constant
if you are using a calculator with a π button, you can use that for pi in this problem.
Otherwise, you can approximate pi. π = 3.14159265359........
A reasonable approximation could be π ≈ 3.14 or π ≈ 3.14159
So to use this formula for the area of circle, we need to find the radius of the circle. In the problem it gives us the diameter.
The radius of a circle is the length of a line from the center of the circle out to the edge.
The diameter of a circle is the length of a line from the edge of the circle, through the middle center of circle, and across to the edge again. It goes from the edge of the circle all the way across to the other side, going through the center point.
Looking at a photo or diagram may be the most easiest way to see this, but the diameter is double the size of the radius. The radius goes from the middle to the edge, and the diameter goes from the edge to the edge, through the middle. So the diameter is like 2 radius' (the plural word for radius is actually radii).
Written as an equation: d = 2r where d = length of diameter and r = length of radius
In the question, we are given that the diameter is 5m, so the radius is half that: 2.5m.
With a radius of 2.5, we can plug that in for "r" in our area formula, and calculate:
A = π r2
A = π (2.52) I'll be using 3.14159 to approximate pi
A = (3.14159) (2.52)
A = (3.14159) (6.25)
A = 19.6349
So this is our area of the circle, but the question asks us to round to the nearest tenth, so that means rounding to one decimal place. And our units are m2 or "meters squared" since its an area not a length. So final answer:
Area of the circle = 19.6 m2
