Area of a circle of radius r is:

To find the area of a circle, we use the standard geometric formula that relates the radius of the circle to the space it occupies on a 2D plane. 1. **Identify the Radius**: The radius is given as $r$, which is the distance from the center of the circle to its edge. 2. **Recall the Formula**: The area $A$ of a circle is calculated by taking the square of the radius ($r^2$) and multiplying it by the constant $\pi$ (approximately 3.14159). 3. **Set up the Equation**: $$A = \pi \times r^2$$ 4. **Conclusion**: The correct expression for the area is $\pi r^2$. Note: $2\pi r$ is the formula for the **circumference** (the distance around the circle), not the area.