The function of surface area units is to quantify or measure the area of objects. Since these are two-dimensional units, they are always expressed in square powers. For example, square centimeter $\left(\operatorname{cm}^2\right)$, square meter $\left(m^2\right)$, square kilometer $\left(\operatorname{km}^2\right)$, and so on.

**Let's analyze a simple exercise:**

We have a rectangle that is $10$ cm long and $7$ cm wide, and we need to calculate its surface area.

In this case, the calculation is quite simple. We will calculate the surface area of the rectangle by multiplying the length by the width, that is, $10cm$ times $7cm$. The result is $70cm^2$. It's crucial to emphasize that since we multiply cm by cm, the result is given in $cm^2$, meaning cm squared(cm raised to the second power).