Rewriting Formula

• Sep 15th 2011, 02:34 PM
vaironxxrd
Rewriting Formula
Hello forum, Vairon here.
I'm having trouble rewriting any kind of formula but I can hopefully understand the first one and use it as reference.

Solve for r
$C&=2&\pi&r$
I assume
C/2r*pi should solve it
• Sep 15th 2011, 02:48 PM
TheChaz
Re: Rewriting Formula
Not exactly. If you divide both sides by $2 \pi r$, you get "1" on the right hand side, not r!

So just divide by $2 \pi$ to get $r = \frac{C}{2 \pi}$
• Sep 15th 2011, 02:54 PM
vaironxxrd
Re: Rewriting Formula
Quote:

Originally Posted by TheChaz
Not exactly. If you divide both sides by $2 \pi r$, you get "1" on the right hand side, not r!

So just divide by $2 \pi$ to get $r = \frac{C}{2 \pi}$

I feel proud I actually got it before the response thanks though btw just to know I'm doing everything right I got this one answered.

Area of a triagle
Solve for b : $A&=\frac{1}{2}&bh$

I solved it : $\frac{A}{\frac{1}{2}*h}&=b$

(Rock)
• Sep 15th 2011, 02:55 PM
skeeter
Re: Rewriting Formula
$b = \frac{2A}{h}$
• Sep 15th 2011, 02:58 PM
vaironxxrd
Re: Rewriting Formula
Quote:

Originally Posted by skeeter
$b = \frac{2A}{h}$

Will mine work?
I tried plugin in the numbers and both formulas output the same number
• Sep 15th 2011, 03:13 PM
skeeter
Re: Rewriting Formula
Quote:

Originally Posted by vaironxxrd
Will mine work?
I tried plugin in the numbers and both formulas output the same number

it'll work, but you're expected to be able to clear any fraction "inside" another fraction.
• Sep 15th 2011, 03:18 PM
vaironxxrd
Re: Rewriting Formula
Quote:

Originally Posted by skeeter
it'll work, but you're expected to be able to clear any fraction "inside" another fraction.

I'm sorry to ask this but why is it 2?

Flip and multiply?
• Sep 15th 2011, 03:20 PM
TheChaz
Re: Rewriting Formula
Quote:

Originally Posted by vaironxxrd
I'm sorry to ask this but why is it 2?

Flip and multiply?

Roughly speaking, yes.
• Sep 16th 2011, 06:45 AM
Prove It
Re: Rewriting Formula
Quote:

Originally Posted by vaironxxrd
I feel proud I actually got it before the response thanks though btw just to know I'm doing everything right I got this one answered.

Area of a triagle
Solve for b : $A&=\frac{1}{2}&bh$

I solved it : $\frac{A}{\frac{1}{2}*h}&=b$

(Rock)

\displaystyle \begin{align*} A &= \frac{1}{2}bh \\ 2A &= 2\cdot \frac{1}{2}bh \\ 2A &= bh \\ \frac{2A}{h} &= \frac{bh}{h} \\ \frac{2A}{h} &= b \end{align*}
• Sep 16th 2011, 07:57 AM
Wilmer
Re: Rewriting Formula
Quote:

Originally Posted by vaironxxrd
Solve for b : $A&=\frac{1}{2}&bh$

or start off by multiplying both sides by 2:
2A = bh ; then:
b = 2A / h
Done.