Question: User: surface of cylinder base ?
1. **Problem Statement:** Find the surface area of the base of a cylinder.
2. **Formula:** The base of a cylinder is a circle. The area $A$ of a circle is given by the formula:
$$A = \pi r^2$$
where $r$ is the radius of the base.
3. **Explanation:** To find the surface area of the base, you only need the radius of the cylinder's base.
4. **Example:** If the radius of the base is $r$, then the surface area of the base is:
$$A = \pi r^2$$
This is the total area of the circular base of the cylinder.
5. **Summary:** The surface area of the base of a cylinder is simply the area of a circle with radius $r$, which is $\pi r^2$.