Answer:
4.9x + 5y
Step-by-step explanation:

Answer:
r=4 d=8 a = 16π c = 8π
d=6 r=3 a=9π c=6π
a=36π r=6 d=12 c=12π
c=18π r=9 d=18 a=81π
Step-by-step explanation:
hope this helps (:
1) 1 dot
2) figure 1 + 3 dots
3) figure 2 + 5 dots
4) figure 3 + 7 dots
5) figure 4 + 9 dots
and keeps going....
The next figure, takes the solution of last figure and add odd number in increasing order.
In this type of problem, find a matter.
I believe there is more to the question because there is not enough information for a valid answer.