so, they already used 4,885.78 this month, but whatever all five family members can use total for a month is 7,250.50, so since they already used 4,885.78, they have left 7,250.50 - 4,885.78 = 2364.72.

Answer:
1136/295 cm
Step-by-step explanation:
Corresponding lengths of similar figures are proportional.
If we let the radius of the second cylinder be x,
x/6.4 = 7.1/11.8
x = 6.4(7.1/11.8) = 1136/295 cm
3/4 divided by 1/5 = 3 3/4
Hope that helps :)
Cut the 4 corners off and you will have an 8-sided octagon