c=2 pi r get rid of r?
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Originally Posted by turbod15b c=2 pi r get rid of r? $\displaystyle c=2\, \pi\, r$ divide both sides by $\displaystyle 2\, \pi$ to get: $\displaystyle \frac{c}{2\,\pi}=r$, or: $\displaystyle r=\frac{c}{2\,\pi}$ RonL
ty if pi=3.142 and c=2.84cm how do i find 'r' ? to 2 significant numbers? 3.142*2.84=8.9?
Last edited by turbod15b; Dec 5th 2006 at 09:23 AM.
Originally Posted by CaptainBlack $\displaystyle c=2\, \pi\, r$ divide both sides by $\displaystyle 2\, \pi$ to get: $\displaystyle \frac{c}{2\,\pi}=r$, or: $\displaystyle r=\frac{c}{2\,\pi}$ RonL Originally Posted by turbod15b ty if pi=3.142 and c=2.84cm how do i find 'r' ? to 2 significant numbers? 3.142*2.84=8.9? Please see CaptainBlack's post. $\displaystyle r = \frac{c}{2 \pi} = \frac{2.84 \, cm}{2 \cdot 3.142} = 0.45191 \, cm = 0.45 \, cm$ -Dan
aint it 28.4/(2x3.142)=4.5 > 2 significant numbers radius = circumference/(2*pi)
Originally Posted by turbod15b aint it 28.4/(2x3.142)=4.5 > 2 significant numbers radius = circumference/(2*pi) (shrugs) You posted "2.84" in your last post. Either way, the problem is done the same way. I'm not sure, did you have a question about 4.5 having 2 significant figures? -Dan
yeh i meant 28.4cm sorry
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