Answer:
78.4
Step-by-step explanation:
4= √([2d)/9.8]
you square both sides to eliminate the square root so you get
4^2=√([2d)/9.8] ^2
16=2d/9.8
then you multiply both sides by 9.8 and you get
156.8=2d
then you divide both sides by 2 to leave d by itself and get
d=78.4
