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Apothem The apothem of a regular polygon is a line segment from the center to the midpoint of one of its sides. Equivalently, it is the line drawn from the center of the polygon that is perpendicular to one of its sides. The word "apothem" can also refer to the length of that line segment. Regular polygons are the only polygons that have apothems. Because of this, all the apothems in a polygon will be congruent and have the same length. For a regular pyramid, which is a pyramid whose base is a regular polygon, the apothem is the slant height of a lateral face; that is, the shortest distance from apex to base on a given face. For a truncated regu
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submitted by pantpranav (367 m) on 1 May 2008 19:04:17 IST (5 comments 251 views)
The 11 RuleYou likely all know the 10 rule (to multiply by 10, just add a 0 behind the number) but do you know the 11 rule? It is as easy! You should be able to do this one in you head for any two digit number. Practice it on paper first! To multiply any two digit number by 11: For this example we will use 54. Separate the two digits in you mind (5__4). Notice the hole between them! Add the 5 and the 4 together (5+4=9) Put the resulting 9 in the hole 594. That's it! 11 x 54=594 The only thing tricky to remember is that if the result of the addition is greater than 9, you only put the "ones" di
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submitted by Selvaganesh_i (273 m) on 10 Feb 2008 21:05:34 IST (1 comments 135 views)
Hello again I've found this from www.eformulae.com and as i thought it to be useful pasting it over here Top Trigonometric Identities: Top Pythagorean Identities:
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submitted by swashata4iit (880 m) on 29 Aug 2007 14:33:14 IST (4 comments 155 views)
A few methods for speed:When performing any of these multiplication algorithms, the multiplier should have as many zeroes prepended(prefixed) to it as there are digits in the multiplicand. This will provide room for any carrying operations. For instance, when multiplying 366 × 7, add one zero to the front of 366 (write it "0366"); when multiplying 985 × 12, prepend two zeroes to 985 ("00985"). Each digit but the last, including the prepended zeroes, has a neighbor, i.e., the digit on its right.To multiply by 12: Starting from the rightmost digit, double each digit and add the neighbor. This gives one digit of the result. If the answer is greater than 1 digit simply
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submitted by vagee (133 m) on 31 May 2007 16:41:09 IST (3 comments 517 views)
Ever wonder how to determine the square root of a number without the aid of a calculator? Believe it or not, people used to do this. Here's one method for doing so. If you're good with long division, here's a quick way to find pretty accurate square roots without the aid of a calculator. Let's try 24.6. Make a guess. It can be a very bad guess. It doesn't matter. You can even guess 1. Let's try 5 since 52 is 25, which is pretty close to 24.6. Divide 24.6 by 5. 24.6 / 5 = 4.92. Now, comes the trick: Pick a new guess between 5 and 4.92 and divide it into 24.6 again. Let's try 4.95. 24.6 / 4.95 = 4.96. 4.96 is pretty close to 4.9598 which is the actual square r
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submitted by snandkeolyar (126 m) on 27 May 2007 14:59:09 IST (1 comments 107 views)
