Tolong jawab lagi yaa.. mueheheee

U1 = 4 m
U2 = 8 m (4x2)
U3 = 16 m (8x2)
U4 = 32 m (16x2)
U5 = 64 m (32x2)
** semuanya dikali 2 **

panjang tali semula
4m + 8m + 16m + 32m + 64m = 124 m

un = a x r^ n-1
64 = 4 x r^5-1
64 = 4 x r^4
64 / 4 = r^4
16 = r ^4
16 akar 4 = 2

Sn = a x r^n -1 /r-1
      = 4 x 2 ^5-1 / 2-1
      = 4 x 32 -1/1
      = 4 x 31
      = 124