how many sqaures would there be in figure 25?

Question

figure number, n    number of squares, s

          1                                 6 

          2                                  9

           3                                 12 

           4                                  15

thats the table for my question. the expression is : 3n+1 and i need to find out how many squares are in figure 25 and how i got my answer!!!!?

Answer 1

y=3*(n+1)

for n=25...3*26=78