Find the value of 
please help friends.

What is the solution to the equation? k/6.4=8.7 2.3 5.568 15.1 55.68

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much

Aball is dropped from a height of 10m above the ground. it bounce to 90% of its previous height on each bounce. what is the approximate height that the ball bounce to the fourth bounce?