Answer:
828.1m
the formula is t = square root of d/4.9
the given is the time which is 13secs
substitute the value of 13s to the t, then square the two sides
(13)^2 = (square root of d/4.9)^2
169 = we cancel the square root because of the exponent of 2
169 = d/4.9 – we cross multiply the two
then that's your answer
