What is the formula for the area of a circle, relevant for calculating the area of a cylinder?

The formula for the area of a circle is given by πr². This formula is essential when calculating the area of the base of a cylinder, as the base of a cylinder is a circle. In this formula, r represents the radius of the circle, and squaring the radius and multiplying it by π provides the total area contained within that circular boundary.

To put it in context, when you calculate the volume of a cylinder, which is commonly done in practical hydraulics, you need the area of the base (the circle). This area is then multiplied by the height of the cylinder to find the total volume. Consequently, understanding and applying the correct formula for the area of a circle is fundamental to further calculations in hydraulics involving cylinders.