The middle section is n(n+1)
The top row is n+2
The bottom row is 2n+1
So the rule for the total number of tiles will be the sum of the above rules...
s(n)=n(n+1)+n+2+2n+1
s(n)=n^2+n+n+2+2n+1
s(n)=n^2+4n+3

with y equaling the total and x equaling the number if months
Choices "a" and "c" will form triangles
Answer:
vdv
Step-by-step explanation:
vfvfvdv
One thousandths. make sure you add the ths because it is a decimal