Answer:
guidance
Step-by-step explanation:
divide the amount by the total cost to get cost per product and add it until you find the amount!

looking at the picture above... you do have the radius, is just in the truncated part of the picture... so you have "h" and "r", so just plug them in
You could solve this mathematically but i mean you could use your eyes.... Its most likely C
;)
Why not write all of the numbers in decimal fraction form, to make them easier to compare?
68 2/3 = 68.666...
72 1/2 = 72.500
68 3/10 = 68.300
74 7/11 = 74.636...
68 1/2 = 68.500
550/8 = 68.750
Now ask yourself: Which of the last four numbers is between 68.666.. and 72.500?