What does perimeter refer to in geometry?

Perimeter in geometry is defined as the sum of the lengths of all the edges or sides of a polygon. This concept is crucial for calculating the boundary length of various shapes, such as triangles, rectangles, and many more. When you measure the perimeter, you are essentially finding out how far one would travel if they were to walk around the shape, tracing along its sides.

For instance, if you had a rectangle with lengths of 5 units and 3 units, the perimeter would be calculated by adding the lengths of all four sides together: 5 + 3 + 5 + 3, resulting in 16 units. Understanding perimeter is fundamental in geometry as it has practical applications in real life, such as determining fencing needed for a yard or the border for a garden.