Solve d = 1/2at^2 for t. Assume all values are positive.

T is equal to the square root of 2d/a.

First, you would have to multiply both sides by 2 to get rid of the 1/2. Then, divide both sides by a.

You will have

2d/a = t^2

Now, just take the square root of both sides and you solved for t.