Question 297672
One problem at a time.
No similar problems.
 Limit 4 problems a day
Use correct category.
Wow! 4 violations at once!

Please help, neither me nor my parents understand this.
In English, we would say:
"Please help. Neither my parents nor I understand this"
You wouldn't say "me  understand"
It is still polite and correct grammar to list yourself last.

Hints.
Direct variation  y=kx where k is some number/constant
Indirect or inverse variation y=k/x 
Proportion means in the form of a fraction
Your first problem would be v=k*r^3
Check out these links.
<a href ="http://www.freemathhelp.com/direct-variation.html">direct variation</a>
<a href="http://mathforum.org/library/drmath/sets/select/dm_direct_indirect.html">directly and inversely</a>
<a href="http://www.cliffsnotes.com/study_guide/Proportion-Direct-Variation-Inverse-Variation-Joint-Variation.topicArticleId-38949,articleId-38907.html">jointly</a>