A ball is dropped off the balcony of a hotel room and it takes 2.8s to fall to the ground. how high above the ground is the ball

The height of the ball above the ground is 38.45 m

First we will calculate the velocity of the ball when it touch the ground by using first equation of motion

v=u+gt

v=0+9.81*2.8

v=27.468 m/s

now the height of the ground can be calculated by the formula

v=√2gh

27.468=√2*9.81*h

h=38.45 m