Variations expressions

Question

The distance that a free falling object falls is directly proportional to the square of the time it falls (before it hits the ground). If an object fell in 76 ft in 3 seconds, how far will it have fallen by the end of 7 seconds?

Answer 1

D = k * t^2

76 = k * 3^2

76 = 9*k

k = 76/9

D = (76/9)*7^2 = 413 and 7/9