C=11.27π feet
Diameter=11.27 feet. Hope it help!
Yes it proportional because they all function of y=3x
0x3=0
2x3=6
4x3=12
6x3=18
answer: 60
age difference is 30 years
10x4=40
40-10=30
when she is 30 he will be 60 because 30(her age) + 30 (age difference) = 60
55/20 = 2.75
It costs $2.75 per person