A baby weighing $8$ pounds compresses the spring of a baby scale 5 millimeters. Use Hooke s Law to determine the weight of a baby that compresses the spring $4$ millimeters. Round your answer to one decimal place.

A) $5.8$ pounds
B) $7.4$ pounds
C) $7.2$ pounds
D) $5.2$ pounds
E) $6.4$ pounds

Hooke's Law states that the force needed to compress or extend a spring by some distance is proportional to that distance. Given that an 8-pound baby compresses the spring 5 millimeters, we can set up a proportion to find the weight of a baby that compresses the spring 4 millimeters: $8\text{ pounds}/5\text{ mm}=x\text{ pounds}/4\text{ mm}$ . Solving for $x$ gives $x=(8\times 4)/5=32/5=6.4$ pounds.