Each side of the first figure is one unit copy and complete the table then find the function rule for the relationship between the figures number and the parameter

Perimeter of a shape is the total length of its border

Figure 1, perimeter = 5 units
Figure 2, perimeter = 7 units
Figure 3, perimeter = 9 units
Figure 4, perimeter  = 11 units

Notice that the perimeter is forming an Arithmetic sequence; 5, 7, 9, 11 with a common difference of 2

The general form of an Arithmetic sequence is 



Where 'd' is a common difference and 'n' is the number of terms.

We have d = 2, and
zero term = the term before the first term = 3

 ⇒ This is the rule to find the perimeter of the next figures