There is 1.4 ounces of juice in 7 in3 of tangerines. If you have a sack of tangerines which each have a diameter of 2 inches, approximately how many tangerines do you need to make a 7 ounce glass of juice? (round to nearest whole number)

The first thing you should do for this case is to know the volume of tangerines, which in this case is given by:
 V = (4/3) * (pi) * ((d / 2) ^ 3)
 The diameter of the tangerines is 2 inches
 V = (4/3) * (pi) * ((2/2) ^ 3) = 4.19 in ^ 3
 Then, you must know by a rule of three how much in^3 of tangerines you need to have 7oz of juice.
 1.4 ---> 7
 7 ---> x
 Clearing x we have:
 x = (7 / 1.4) * (7) = 35 in ^ 3
 It takes 35 in3 of tangerines to make 7 ounces of juice.
 Then, the number of tangerines will be:
 n = (35) / (4.19) = 8.35
 nearest whole number:
 n = 9
 answer
 you need 9 tangerines to make a 7 ounce glass of juice