The formula πr² (pi times the radius squared) is used to calculate the area of a circle.
Here's a breakdown of how to use it:
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Identify the radius (r) of the circle: The radius is the distance from the center of the circle to any point on its edge. If you're given the diameter (the distance across the circle through the center), divide the diameter by 2 to find the radius.
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Square the radius: Multiply the radius by itself (r * r = r²).
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Multiply by pi (π): Pi is a mathematical constant approximately equal to 3.14159. You can use 3.14 for most calculations, or use the π button on your calculator for more precision.
*Therefore, the area of the circle = π r²**
Example:
Let's say you have a circle with a radius of 5 cm.
- Radius (r) = 5 cm
- *Radius squared (r²) = 5 cm 5 cm = 25 cm²**
- Area = π 25 cm² ≈ 3.14159 25 cm² ≈ 78.54 cm²
So, the area of the circle is approximately 78.54 square centimeters.
In summary, to find πr², simply square the radius of the circle and multiply the result by pi.
