Learn how to calculate the areas of rectangle, triangle, and circle in Excel for a single cell or range of cells usin this formula.

Why is the area of a circle proportional to the square of its radius? And why is that ratio the same as the ratio of the circumference to the diameter?

The area of the rectangle is length × width, π𝒓 × 𝒓 = π𝒓². The formula for the area of the circle is 𝑨 = π𝒓². To work out the area of a circle: Find the value of the radius.