Answer: Definition of Vertical Angles.
1st drop : 48
1st bounce:24
2nd drop : 12
2nd bounce: 6 and so on and so forth:
This is a geometric progression with 1st term a = 48 and common ratio r= 1/2
The sum of all terms in a G.P is
S=a(1 - rⁿ⁻¹)/(1-r),
S = 48(1 - r⁴)/(1-r). Replace r by 1/2
S = 48[1-(1/2)⁴]/(1/2)
S = 90 ft
