Question

The variable r is directly proportional to the square of t, and r = 144 when t = 72.

Answer 1

Answer:

k=0.023

Step-by-step explanation:

$r \alpha {t }^{2} \\ r = k {t}^{2} \\ 144 = k \times {72 }^{2} \\ k = \frac{144}{ {72 }^{2} } \\ k = 0.023 \\ the \: eqn \: is \: therefore \\ r = 0.023 \times {t}^{2}$