The base area refers to the surface area of the bottom face of a three-dimensional shape, such as a cube, cylinder, or pyramid. It is an important measurement used in geometry to calculate the volume of these shapes. The base area is typically expressed in square units, such as square meters or square feet. To find the base area, you use specific formulas depending on the shape. For example, the base area of a rectangle is calculated by multiplying its length by its width, while the base area of a circle is found using the formula πr², where r is the radius.