Picture enclosed. I answered the first two questions; although, I need help answering the last question. Can you explain this to me? I've been stuck on this for hours. :/

Question

technodynamic · Answer

attachment

anonymous · Answer

i got 24.9 or 25 second's!

anonymous · Answer

because to get the time of something to hit the ground you use this formula : t=√(S(4.9) and S=the height of the object in feet and 38.53 meters in feet is 126.4 feet! then just plug it in!

technodynamic · Answer

I typed it in, but it didn't accept that answer. 
I also tried solving it this way, $$(-24.5 \pm \sqrt{(24.5)^2-4(-4.9)(7.9})/(2(-4.9))$$
But still the answer was incorrect when I used the formula :/

anonymous · Answer

is it rounded to the nearest hundred?

anonymous · Answer

idk man , i would try and google it...