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The Formula for the Area of a Circle
publish date: 2026/05/17 19:43:26.826380 UTC
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When a circle is cut into many equal pie-shaped pieces and rearranged, the result resembles a parallelogram whose base is half the circumference and whose height equals the radius.
The area of a circle with radius \(r\) is given by the formula:
\[A = \pi r^2\]
In the expression \(\pi r^2\), what operations are indicated?
Correct Answer
Square r first, then multiply by π
Explanation
In the expression \(\pi r^2\), the notation means \(\pi \times r^2\). Because the exponent applies only to \(r\), you must evaluate the exponent first: square \(r\) to get \(r^2\), then multiply by \(\pi\). This follows the order of operations.
Reference
Mathematics for college students