Question 923717
The distance a ball rolls down an inclined plane is directly proportional to the square of the time it rolls. 
 D is directly proportional to the square of the Time it rolls
D = kt^2
Where k is the factor of proportionality.
To find the value of k.
k = D/t^2
During the first second the ball rolls 8 feet.
k = 8/1^1
k = 8
Formula: k = 8t^2
How far will the ball roll during the first 3 seconds?
Distance = 8 x 3^2
Distance = 72 feet.

Hope this helps.
:-)