The foot length of Sandy is 10.5 inches
Solution:
Assume nose and foot length are proportional
Therefore,

Let "n" be the nose length and "f" be the foot length
Then,

n = kf ------ eqn 1
Where "k" is the constant of proportionality
Cindy's nose is 1.9 inches long and her foot is 9.5 inches long
n = 1.9 inches'
f = 9.5 inches
Substitute these in eqn 1

Thus k = 0.2
Sandy's nose is 2.1 inches long, we have to find the foot length
n = 2.1
k = 0.2
f = ?
Substitute these in eqn 1

Thus foot length of Sandy is 10.5 inches