Which of the following best defines the perimeter of a shape?

The perimeter of a shape is defined as the total distance around the outside of that shape. To find the perimeter, you measure the lengths of all the sides of the shape and add them together. This concept applies to various geometric figures, whether they are polygonal (like triangles, rectangles, and pentagons) or circular, where the perimeter is referred to as the circumference.

The area inside a shape refers to a different measurement altogether, quantifying the amount of space contained within the boundaries of the shape. The sum of the angles of a shape is related to its geometry, particularly in polygons, but does not inform us about distances around it. Lastly, the length of one side describes just a part of a shape and does not capture the entirety of perimeter measurement, which encompasses all sides. Thus, the best definition of perimeter is indeed the total distance around the outside of a shape.