Jawabanmu

2014-03-10T22:31:09+07:00
U1 = a = 4 cm
U5 =  ar^{4} = 324 cm
 \frac{U5}{U1} =  \frac{ ar^{4} }{a} =  \frac{324}{4} = r^{4} =81  

r = 3
S5 = 4 + 4.3 + 4.3.3 + 4.3.3.3 + 4.3.3.3.3 = 484 cm = 4,84 m