Wikipedia:Reference desk/Archives/Mathematics/2007 January 12

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January 12

Pie chart question

how do you find a central angle in a pie chart

$angle=2\pi {\frac {part}{total}}$, where angle is given in radians (change 2π to 360 for degrees), part is the partial amount represented by the slice and total is the total amount represented by all slices. — Kieff 02:19, 12 January 2007 (UTC)

This has been nagging at me, so I'm going to point out that the markup here is wrong. When we write "part", TeX sees that as the product of p times a times r times t, and typesets it accordingly. Instead, use "\text{part}" or "\mathrm{part}" or "\mathit{part}", like so.

${\begin{aligned}{\text{angle}}&{}=2\pi {\frac {\text{part}}{\text{total}}}&&\qquad {\text{(text, preferred)}}\\\mathrm {angle} &{}=2\pi {\frac {\mathrm {part} }{\mathrm {total} }}&&\qquad {\text{(mathrm)}}\\{\mathit {angle}}&{}=2\pi {\frac {\mathit {part}}{\mathit {total}}}&&\qquad {\text{(mathit)}}\end{aligned}}$

In other contexts we need the name of an operator, such as "sin" or "fixedpoint". Common operators like the sine function are already defined, so we just prefix with a backslash: "\sin". Uncommon operators can be designated as such: "\operatorname{fixedpoint}".

${\begin{aligned}s_{binary}&{}=fixedpoint(sin\theta )&&\qquad {\text{(wrong)}}\\s_{\text{binary}}&{}=\operatorname {fixedpoint} (\sin \theta )&&\qquad {\text{(right)}}\end{aligned}}$

Please take an extra moment to help keep our equations looking professional. Thanks! --KSmrq^T 03:49, 16 January 2007 (UTC)

I used to do this, but using \mbox (that's probably incorrect too), but I kinda lost the habit... Anyway, thanks for pointing these out, I'll remember next time. :) — Kieff 05:23, 16 January 2007 (UTC)