Talk:Frustum

message: : I think that some of the calculations on the page are missing. --Proficient 07:10, 8 April 2007 (UTC)
thread_title: Calculations missing

message: My Maths teacher said it is a frustrum and not a frustum was this just misprnounciation on her part or can it actually be called a frustrum
:A mathematician and linguist replies:  The spelling frustrum is erroneous, according to the Oxford English Dictionary, and they know what they are talking about. This misspelling probably comes about because the other word beginning "frust..." that everyone knows is "frustrate". So, anonymous poster, I'm afraid your maths teacher was incorrect. Teachers can be wrong too, alas. — Paul G 12:10, 17 May 2007 (UTC)
replies: text: I suppose that frusta must be commonly perceived to be very frustrating polyhedra. Double sharp (talk) 15:07, 8 November 2013 (UTC)
thread_title: Frustum or frustrum?

message: 198.28.92.5 07:43, 24 May 2007 (UTC)
thread_title: Incorrect formulas for areas

message: The article explicitly defines B sub 1 to be the smaller base and B sub 2 to be the larger in the section Formulae > Volume.  However, in the image 'frustum with symbols.svg' has these two bases labeled in the opposite way.  
AnandaDaldal (talk) 21:02, 23 February 2010 (UTC)
thread_title:  Text and image don't agree. 

message: Is it really so pathetic that we need to write the value of pi?(after linking it to the article 'pi')
Just below the formula for volume of conical frustum.Gauravjuvekar (talk) 16:08, 6 January 2012 (UTC)
replies: text: Quite. It is unlikely that someone reading this article and able to comprehend the formulae is unaware of the approximate value of π. I removed it. ehn (talk) 05:27, 26 May 2020 (UTC)
thread_title:  pi=..... 

message: Frustum means "piece cut off" in Latin. Please add the same.Gauravjuvekar (talk) 16:16, 6 January 2012 (UTC)
thread_title:  latin 

message: According to the article, "a frustum is the portion of a solid that lies between one or two parallel planes cutting it." Now, any bounded volume can be constructed this way, meaning that any bounded volume is a frustum? Is this correct, or have I missed something? So basically, frustra ares just the set of volumes that either are bounded, or for which there is some vector  such that the scalar product between the position of each point in the volume and  is bounded (this include all bounded volumes as well)? —Kri (talk) 05:32, 20 January 2022 (UTC)
replies: text: It's definitely not true that every bounded volume, or even every finite polyhedron, has two parallel faces. —Tamfang (talk) 00:27, 30 October 2023 (UTC)
thread_title:  Is there and bounded volume that is NOT a frustum? 

message: Is there a source for the computation of the surface area of the right, polygonal frustum? I tried studying a limiting case, and it seems incompatible with the formula presented here. I am considering a regular hexagon with side length L, so its area is 3*sqrt(3)*L^2/2. For a frustum with side lengths L and 0 and perpendicular height 0, we expect its total surface area to be twice that of the regular hexagon, 3*sqrt(3)*L^2. This is not true with the formula as written. This can be recovered if the secant^2 is replaced with a cotangent^2 under the square root. Am I wrong in my thoughts on the limit? 145.101.40.28 (talk) 12:30, 23 October 2023 (UTC)
replies: text: I have computed the lateral surface area myself and find that the cotangent appears in the final formula, not the secant. Here is a link to my proof. I will edit the formula accordingly. 145.101.40.28 (talk) 14:03, 23 October 2023 (UTC)
replies: text: And I have a final argument. The side length and circumscribing radius are related via a = 2*r*sin(pi/n). The formula with the secant does not reduce to the circular case as n tends to infinity, but it does with the cotangent. 145.101.40.28 (talk) 14:42, 23 October 2023 (UTC)
thread_title:  Potential error in the surface area of a right polygonal frustum?