If the lengths of an object are measured in feet, then the area of the object will be measured in what measurement?

Square feet.

Step-by-step explanation:

Feet are an example of what are called linear units. They're used to measure one dimensional things like length, width, or height. Area is two-dimensional, it takes up (flat) space, so we need to measure it in units that do the same thing. The simplest two-dimensional shapes to measure area with turn out to be squares (since the area of a square with side length s is just s²), so we usually measure area in square units. Since our linear units here are feet, the corresponding square units will be square feet.