Let volleyball be v and let basketball be b.
v : b = 4 : 7, b = 21
v : 21 = 4 : 7
v/21 = 4/7
7*v = 4*21
v = 4*21/7
v = 4*3
v = 12
Volleyballs are 12
Hope this helps.
Answer:




Solving for
we got
and replacing this we got:



And then the best option for this case would be:
b.csc x
Step-by-step explanation:
For this case we have the following expression given:

We know from math properties that the definition for cot is 
If we use this definition we got:


Now we can use the following identity:

Solving for
we got
and replacing this we got:



And then the best option for this case would be:
b.csc x
90° is the correct answer
The one on the right is 22.

which gives u a price of 22 per gallon