
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
April 7th, 2014, 09:17 AM  #1 
Newbie Joined: Apr 2014 From: Holland Posts: 3 Thanks: 0  First time thread! V=4/3 . PI . R^3 Rewrite as R=....
Hello Peeps, this is my first time posting. My name is Kees I'm 23 years old and Im from Holland. I am a carpenter atm but will start my education to be a construction supervisor which will take 4 years. Recently I started taking math classes and just got my fist grade 7.4! (out of 10) So I was happy since I never had math before. Anyways, Now I am at chapter 9 of my book and I frequently get asked to do formulas like; V=4/3 . PI . R^3 Rewrite as R Now since I am taking a speed course, my teacher doesn't really have the time to go step by step to solve the problem. I was hoping somebody could help me with this. Kind regards, Kees. 
April 7th, 2014, 09:44 AM  #2 
Senior Member Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,211 Thanks: 521 Math Focus: Calculus/ODEs 
Hello and welcome to MMF, Kees! We are given the formula for the volume$V$ of a sphere in terms of its radius $r$: $\displaystyle V=\frac{4}{3}\pi r^3$ And we are asked to solve for $r$. The first thing we want to do is multiply both sides by $\displaystyle \frac{3}{4\pi}$ so that we just have $r^3$ on the right sides: $\displaystyle \frac{3}{4\pi}\cdot V=\frac{3}{4\pi}\cdot\frac{4}{3}\pi r^3$ Divide out the common factors on the right and arrange as: $\displaystyle r^3=\frac{3V}{4\pi}$ Next, we want to take the cube root of both sides so that we just have $r$ on the left: $\displaystyle \sqrt[3]{r^3}=\sqrt[3]{\frac{3V}{4\pi}}$ $\displaystyle r=\sqrt[3]{\frac{3V}{4\pi}}$ This will allow us to determine the radius of a sphere if given the volume. Last edited by MarkFL; April 7th, 2014 at 10:26 AM. Reason: minor typo... 
April 7th, 2014, 10:18 AM  #3 
Newbie Joined: Apr 2014 From: Holland Posts: 3 Thanks: 0 
Edit.... I GOT IT! Because dividing 4/3pi by 3/4pi makes them cancel out! MANNNN O MANN!! Thanks BRO! I love you.

April 7th, 2014, 10:23 AM  #4  
Senior Member Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,211 Thanks: 521 Math Focus: Calculus/ODEs  Quote:
Incidentally, to write fractions with $\LaTeX$, use the command: \frac{numerator}{denominator} and to write special characters like $\pi$, use the command \pi.  
April 7th, 2014, 10:25 AM  #5 
Newbie Joined: Apr 2014 From: Holland Posts: 3 Thanks: 0 
Ehmmm Latex? I said I love you but I think your moving to fast :P Jk. Thanks for your help mark. I am gonna continue with my homework. You help me get one step closer to my goal of being a supervisor in construction! I'll be back! 
April 8th, 2014, 01:57 AM  #6 
Senior Member Joined: Mar 2014 Posts: 112 Thanks: 8 
$\displaystyle \boxed{r\,=\,\sqrt[3]{\frac{3V}{4\pi}}\,=\,\sqrt{\frac{A}{4\pi}}}$

April 8th, 2014, 02:00 AM  #7 
Senior Member Joined: Mar 2014 Posts: 112 Thanks: 8 
. . . $\displaystyle =\,\boxed{\frac{1}{2}\sqrt{\frac{A}{\pi}}}$


Tags 
rewrite, thread, time, v4 or 3 
Search tags for this page 
v=4/3pir^3 solve for r,4/3pie,v=4/3πr3 solve for r,v=4/3pir^3,4 pi r cubed divided by 3,v=4 pi r^3/3,4/3 pi,Derivation of formula v=4/3pi r3,3pir,4/3pi r3,V=4/3pir^3 for pi,v=4/3 pi r^3,in c program v=4/3pir^3 pir^2h,given that V =4/3pir^3 and A=4pir^2,find dA/dV.,4/3pir^3
Click on a term to search for related topics.

Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Please Disregard Previous Thread!  nigerianscholar  Academic Guidance  0  May 28th, 2013 01:14 PM 
How to rewrite  mathkid  Calculus  2  September 16th, 2012 04:11 PM 
Yet another (?) movie thread  NClement  New Users  6  August 8th, 2008 11:41 PM 
Mathematical Humor Thread  Infinity  New Users  4  September 26th, 2007 07:50 AM 