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Answer:
2πr cm
Step-by-step explanation:
The circumference of a circle of radius r is ...
C = 2πr
For a radius of (r cm), the circumference is ...
A = 2π(r cm) = 2πr cm
For a radius of (2r cm), the circumference is ...
B = 2π(2r cm) = 4πr cm
Then the difference between the circumferences is ...
B -A = (4πr cm) -(2πr cm) = 2πr cm . . . . difference in circumference
Find if all the ratios are proportional to 1:8. 2:16 is, so is 3:24, and 4:32. 4.5*8=36, and 5:40 is proportional. 6:48 is, and 6.5*8=52. The table is proportional, just divide the pay by the hours and you should be getting 8.
Part A: c for cost. c=0.31m+0.5
0.31m is the cost per minute. 0.5 is cost per call.
Part B: 0.31m+0.5=5.15 to solve we must rearrange.
subtract 0.5 from each side giving us 0.31m=4.85
divide by 0.31 giving us m=15.65
She will have $500 in 5 days because when she takes out the 20 every week she will have had $100 so to make $500 she will have to have made 5 $100