The measurement of the surface enclosed by a circle.

### Formulas

*A* = \(πr^{2}\) or *A* = \(π\frac{d^{2}}{4}\)

### Example

Consider a circle with a radius of 10 cm.

\(A = πr^{2} = π × 10^{2} = 100π\).

\(A ≈ 314.16\)

The measurement of the surface enclosed by a circle.

*A* = \(πr^{2}\) or *A* = \(π\frac{d^{2}}{4}\)

Consider a circle with a radius of 10 cm.

\(A = πr^{2} = π × 10^{2} = 100π\).

\(A ≈ 314.16\)