Answer:
Step-by-step explanation:
If two variables are directly proportional, it means that an increase in the value of one variable would cause a corresponding increase in the other variable. Also, a decrease in the value of one variable would cause a corresponding decrease in the other variable.
Given that distance, d varies directly with square of the time,t, if we introduce a constant of proportionality, k, the expression becomes
d = kt²
If d = 71 when t = 5, then
71 = k × 5² = 25k
k = 71/25
k = 2.84
The equation becomes
d = 2.84t²
Therefore, when t = 9 seconds, then
d = 2.84 × 9² = 230.04 ft