Talk:Surface area

Two dimensions
Is it really correct that two dimensional structures such as triangles have "surface area" ? I do not think so, "surface area" is a three dimensional concept. Ar


 * I've moved the table of areas of plane figures to the talk page of "Area". Arcfrk (talk) 08:48, 11 March 2008 (UTC)

Surface Area To Volume Ratios
There is a problem with the last section. It states that if you increase the radius the ratio decreases. However, if you change the units of measure, the ratio can increase with a larger radius. A radius of 100 meters has a SA:V ratio of .03, but a radius of 1 kilometer has a ratio of 3. Also, it should be clear that this is assuming cells have a spherical shape. —Preceding unsigned comment added by 70.188.231.137 (talk) 04:05, 30 March 2008 (UTC)
 * SA:V is measured in inverse distance units. It is not dimensionless.  A sphere with a radius of 100 meters has a ratio of 0.03/meter while the sphere with a radius of 1 kilometer has a ratio of 3/kilometer = 3/(1000 meters) = 0.003/meter.  Measuring in the same units, the sphere ten times larger has a ten times smaller ratio, as it should.  This similarity law holds for any shape, not just spheres.  In the case of cells the only assumption is that a big cell is the same shape as a little one.  This is more or less true of cells.  It is definitely not true of multicellular structures, which is why one can easily distinguish a mouse bone from an elephant bone even when the mouse bone is magnified to elephantine size. -Dmh (talk) 05:32, 23

And I am SMART —Preceding unsigned comment added by 66.112.37.98 (talk) 22:33, 2 March 2011 (UTC)

What. The. Hell.
I came here to verify a formula, but I ended up stumbling upon a page a 4th grader could have written. What in the world happened to this article?

S lijin (talk) 01:54, 19 May 2009 (UTC)


 * I came here to verify a formula, but I ended up stumbling upon a page a professor could have written. What in the world happened to this article? i can not understand any of this, perhaps someone could submit something eaiser to understand Summer911 (talk) 05:32, 10 March 2010 (UTC)

Moved from the article
{| class=prettytable !Shape !Area formula derivation The radius of the circular ring is $$ f(x) = \sqrt{r^2-x^2}$$. The length of the circular ring is equal to $$2\pi\cdot f(x)$$ The width of the ring can be determined by using Pythagoras' formula for a rectangular triangle with side lengths $$dx$$ and $$f'(x) \cdot dx$$, which leads to $$\sqrt{1+f'(x)^2}\,dx$$ The infinitesimal surface area of the circular ring thus is equal to $$2\pi f(x)\cdot \sqrt{1+f'(x)^2}\,dx$$ The derivative of $$f(x)$$ is equal to $$f'(x) = \frac{-x}{\sqrt{r^2-x^2}}$$ The surface area of the sphere can be calculated as $$ \int_{-r}^r 2\pi f(x)\cdot \sqrt{1+f'(x)^2}\,dx$$ = $$ \int_{-r}^r 2\pi \sqrt{r^2-x^2} \cdot \sqrt(1+\frac{x^2}{r^2-x^2})\,dx = \int_{-r}^r 2\pi \sqrt {r^2}\,dx = 2\pi r \int_{-r}^r 1\,dx$$ The antiderivative needed is the simple linear function $$x$$ Thus, the sphere surface area amounts to Asphere = $$2\pi r[r-(-r)] = 4\pi r^2$$
 * Sphere
 * The surface area of a sphere is the integral of infinitesimal circular rings of width $$dx$$
 * The surface area of a sphere is the integral of infinitesimal circular rings of width $$dx$$

References recovered partially
http://web.archive.org/web/20120427201949/http://www.math.usma.edu/people/rickey/hm/CalcNotes/schwarz-paradox.pdf — Preceding unsigned comment added by 94.197.120.122 (talk) 22:10, 9 October 2013 (UTC)

http://web.archive.org/web/20111215152255/http://mathdl.maa.org/images/upload_library/22/Polya/00494925.di020678.02p0385w.pdf — Preceding unsigned comment added by 94.197.120.122 (talk) 22:19, 9 October 2013 (UTC)

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Should "Surface Measure" redirect here?
The technical term "surface measure" doesn't have a wikipedia page. Is this the page? Should a redirect come here?

Characterization
The article mentions a characterization of surface area using a few properties such as additivity and invariance under Euclidean motions. There should be given a source for this, and preferably it should also be explained more clearly. MathHisSci (talk) 21:52, 14 April 2023 (UTC)