Jawabanmu

2014-04-28T03:54:41+07:00
Arⁿ-¹=an»»81=16r^5-1. .3⁴=2⁴r⁴...r=3/2 .Sn=a(rⁿ-1)/r-1=16(3/2^5-1)/(3/2-1)
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2014-04-28T04:04:32+07:00
Diket = U1 = 16 cm
U5 = 81 cm

aku ngerjainnya pkek cara cepat, ya
 r^{x-y}  \frac{ U_{x}}{ U_{y} }
 r^{5-1}  \frac{U5}{U1}
 r^{4} [/x] = [tex] \frac{81}{16}
 r^{4} = 5,0625
r =  \sqrt[4]{5,0625}
r = 1,5 cm

Sn =  \frac{a( r^{n} - 1)}{r-1}
 S_{5}  \frac{16 ( 1,5^{5} - 1 )}{1,5 - 1}
 S_{5} = 16 (7,59375-1) / 0,5
S5 = 16 . 6,59375 / 0,5
S5 = 105,5 / 0,5
S5 = 211 cm

jdi, panjang tali keseluruhan adlah 211 cm

semoga membantu :)
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