👉 To calculate the area of a circle, you use the formula \( A = \pi r^2 \), where \( A \) is the area and \( r \) is the radius of the circle. This formula is derived from the concept of integrating the circle's infinitesimally thin rings around its center. The constant \( \pi \) (pi), approximately 3.14159, represents the ratio of the circle's circumference to its diameter. For example, if the radius is 5 units, the area would be \( A = \pi \times 5^2 = 25\pi \) square units, or approximately 78.54 square units when using \( \pi \approx 3.14159 \). This formula is fundamental in geometry and has applications in various fields, including physics and engineering.
