What is defined as the measure of a figure's outer boundary?

Perimeter is defined as the measure of a figure's outer boundary. It is calculated by adding together the lengths of all the sides of the figure. For example, in a rectangle, the perimeter is the sum of the lengths of all four sides, or specifically, twice the sum of the length and width.

In practical terms, knowing the perimeter helps in various real-world applications, such as determining the amount of fencing needed to enclose a yard or the materials required to encircle a particular space.

The other terms represent different measurements: area measures the space contained within a figure, volume measures the space occupied by a three-dimensional object, and length typically refers to the measurement of one dimension of a shape, such as the distance from one point to another. However, when discussing the outer boundary of a shape, perimeter is the appropriate term.