$$\text { If } s \text { varies directly as } t ^ { 2 } \text {, and } s = 144 \text { when } t = 4 \text {, find } s \text { when } t \text { is } 3 \text {. }$$
A) 36
B) 81
C) 108
D) 12

Question

Quizplus · Accepted Answer

Since $s$ varies directly as $t^2$, we can write $s = kt^2$ where $k$ is the constant of variation. Given $s = 144$ when $t = 4$, we can find $k$ by substituting these values: $144 = k(4)^2$, which gives $k = 9$. To find $s$ when $t = 3$, substitute $t = 3$ into $s = kt^2$: $s = 9(3)^2 = 81$.

A) 36 B) 81 C) 108 D) 12

A) 36
B) 81
C) 108
D) 12