C^2+7 would equal 88. the first equation states that C=9, so you can just plug in 9 for C
Honestly no idea... sorry
The volume of a cone is one-third of the product of the area of the base times the height, i.e.
(1/3)π(r^2)*h = (1/3)π(3cm)^2 *(8cm) = 75.40 cm^3
Now multiply that by the number of cones: 6 * 75.40 cm^3 = 452.40 cm^3.
Then the answer is 452 cm^3