Mark bought gifts for his friends, and each gift cost $9. Let y represent the total cost and x represent the number of gifts. Wr
ite an equation to represent the proportional relationship between the total cost and the number of gifts he bought. y = 8x
y = one-eighth x
y = 9x
y = one-ninthx
We all know that 22/7 is a very good approximation to pi. But this well-known fraction is is actually 1/791 larger than a slightly less-well-known but much more mysterious rational approximation for pi: . The fraction 355/113 is incredibly close to pi, within a third of a millionth of the exact value.