Answer:
The relationship is proportional. The constant of proportionality is 20. It represents how many meters the horse runs per second per second. Equation is d=20t
No no no no no no no no no jk its c your welcome
By definition, the number
is the ratio between the circumference and the diameter:

This implies that

And so your circumference is 
8x+4 would be the answer if you combine like terms
Multiply by z to get
wz = xy
divide by x
y = wz/x