What is the formula to calculate the area of a circle?

• A. A = 3.14 * Radius^2
• B. A = 6.28 * Radius^2
• C. A = Radius^2
• D. A = 3.14 * Diameter^2

Answer: (A)

Area comes from how the circle’s size relates to its radius, and it always includes the constant π. The correct formula is area equals π times radius squared. Using π approximated as 3.14 gives area = 3.14 × (radius)^2. This is the right form because the area grows with the square of the radius and incorporates π to account for the circle’s geometry. For example, if the radius is 3 units, the area is about 3.14 × 9 ≈ 28.27 square units.

The other forms don’t fit: using diameter inside the square would yield area = π × diameter^2, which equals 4π × radius^2—four times larger than the correct value. Using 2π × radius^2 would double the correct result, and omitting π leaves just radius^2, ignoring the circle’s curved nature.