Answer:
p = 3n + 2
Step-by-step explanation:
let n be the number of shapes and p the perimeter
We can construct the following table
n : 1 2 3
p : 5 8 11
The differences in p are constant
8 - 5 = 11 - 8 = 3
Thus p = 3n + ?
n = 1 → 3(1) + ? = 5 ⇒ 3 + ? = 5 ⇒ ? = 2
n = 2 → 3(2) + ? = 8 ⇒ 6 + ? = 8 ⇒ ? = 2
n = 3 → 3(3) + ? = 11 ⇒ 9 + ? = 11 ⇒ ? = 2
We require to add 2 to 3n
Thus
p = 3n + 2