Which expression represents the area of a circle?

• A. A = l * w
• B. A = 1/2 * b * h
• C. A = π r^2
• D. A = 2 * b

Answer: (C)

The area of a circle is found by A = π r^2, where r is the radius. This formula shows how area grows with the size of the circle: it depends on the radius squared and on π, the constant that relates a circle’s dimensions to its area. Using the radius directly captures the circle’s size, and multiplying by π converts that size into area in square units. The other familiar shapes have different area formulas—rectangles use length times width, triangles use one-half times base times height—so those expressions don’t apply to a circle.