How do you determine the area of a circle?

How do you determine the area of a circle?

• A. (radius x radius) x 3.14
• B. Pi times radius squared
• C. 2 x Pi x Radius
• D. Pi times diameter

Answer: (A)

The area of a circle is found using A = π r^2, which means you multiply the radius by itself and then multiply by π. In basic problems, using an approximation for π such as 3.14 is common, so writing (radius × radius) × 3.14 gives an approximate area. That’s why this form matches the standard idea of A = π r^2, just with a numerical substitute for π. The other expressions aren’t area formulas: 2 × π × radius is the circumference, not area; π × diameter is also tied to the circumference (since diameter is 2r, π × diameter equals 2πr). The form π × radius squared is the same idea as the chosen one, just using the symbol π instead of a numeric 3.14, which is why the option with 3.14 is the test’s expected answer.

The area of a circle is found using A = π r^2, which means you multiply the radius by itself and then multiply by π. In basic problems, using an approximation for π such as 3.14 is common, so writing (radius × radius) × 3.14 gives an approximate area. That’s why this form matches the standard idea of A = π r^2, just with a numerical substitute for π.

The other expressions aren’t area formulas: 2 × π × radius is the circumference, not area; π × diameter is also tied to the circumference (since diameter is 2r, π × diameter equals 2πr). The form π × radius squared is the same idea as the chosen one, just using the symbol π instead of a numeric 3.14, which is why the option with 3.14 is the test’s expected answer.