Working with time and dropping from a specified height

[averyjedwards2]

hello there! I've been working on math for a while, and on y math homework there's a specific question that i just don't know of the correct formula to solve it. i can do algebra quite well, i just can't recall what this specific formula may be. here is my question:
A construction worker is working on the roof of a building. a drop of paint falls from a rafter that is 225 feet about the ground. after how many seconds does the paint hit the ground?

 

[MarkFL]

If we ignore drag, then a freefalling body near the surface of the Earth experiences a constant acceleration of about 32.2 ft/s/s. So, we know the distance $d$ (225 ft), the initial velocity $v_0 = 0$, and the acceleration $a$, and we need the time to cover that distance. A useful formula is thus:

$$t=\sqrt{2ad+v_0^2}$$

Can you proceed?