To calculate the area of a circle, which formula is used?

The formula for calculating the area of a circle is derived from the relationship between the circle's radius and diameter. The correct formula states that the area is equal to π multiplied by the square of the radius. However, it can also be expressed in terms of the diameter, since the diameter is twice the radius.

When using the diameter in the formula, the correct relationship is that the area can be represented as π multiplied by the square of the diameter divided by 4. This reflects the fact that the radius is half the diameter (radius = diameter/2). Therefore, when calculating area using diameter, the diameter must be squared, and since the radius is half the diameter, squaring that would give a formula consistent with the area calculation:

Area = π x (D/2)² = π x (D²/4).

Hence, the formula provided is valid and confirms the correct calculation for the area of a circle using the diameter.

In contrast, the other options either incorrectly represent the formula or do not relate correctly to the area calculation. For instance, using the square of the radius directly without relating it to the diameter is a standard form but does not align with the expression in option D, which is a variation for calculating with