The side of a rectangular pentagon is denoted by l. Express the perimeter of the pentagon using the variable l.

Hint: In order to find the perimeter of the pentagon, we need to calculate the number of sides in a pentagon and then we just need to multiply the number of sides to the value of length of a side of pentagon to find the value of its perimeter.

Complete step-by-step answer:
Given Data,
Side of pentagon has value l
We know, perimeter is the total length of all the sides of a polygon, i.e. sum of all sides.
A pentagon is a geometrical figure which has 5 sides and looks as follows,

Given the length of a side of the pentagon is l.
Therefore the perimeter of a pentagon = number of sides × length of each side
P = 5 × l
P = 5l
Hence the perimeter of the pentagon is 5l.

Note – In order to solve this type of problems the key is to know the definition and the respective formulae to find the perimeter of a polygon. Perimeter is denoted in units of order one. It is represented by P. It can be directly found by having the length of one side in regular polygons. In irregular polygons we need the length of each side to find the perimeter.