Author: Christopher
•10:17 AM
Yeah, I'm a geek. I came across this cool little method to make an equilateral triangle, and had to share:

The principles of geometry were recorded in a series of theorems expounded by the Greek mathematician Euclid around 300 BCE. One of the first principles he alludes to is a process of dividing a straight line into two equal parts. This is done by taking the line, AB, and drawing two circles of equal diameter, one circle at each end of the line, so that they overlap.

Drawing a vertical line between the points C & D will bisect the line AB into two equal lengths. This concept can be taken one stage further when the circles, both of equal diameter, are drawn such that the circumference of one circle touches the centre of the other circle. This geometric pattern was well known to the ancients and has been passed down to us with the title Vesica Piscis. The resultant area where the two circles overlap is known as the Vesica.

It produces some interesting characteristics. For example, it is possible from this use of the two circles to determine an angle of 30° and 60°. This is shown in the diagram below


through the points where the 60° is defined by the points ACB. The bold line at an angle represents the hypotenuse of a right angle triangle, CBA. Thus, the opposite angle, BAC, is 30°. By turning this simple relationship into a rectangle (as shown by the dotted lines) and bisecting the angles with a pair of compasses, it is possible to create the angles 15°, 30°, 45°, 60°, 75° and 90°. Thus, with a simple pair of compasses and a straight edge, eg 24 inch gauge, our ancestors were able to determine the primary geometric angles regularly used.

This simple geometric structure immediately lends itself to the construction of another important figure -the equilateral triangle.

So, our ancestors, through their knowledge of geometry, were able to produce, with considerable accuracy, the three most common geometric forms in their construction armoury -the circle, the square and the equilateral triangle -the latter two being derived from the basic form -the circle.


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1 comments:

On December 5, 2010 at 9:12 PM , SacrificeofPraise said...

geek! ;) I blanked out in the first paragraph! KISSES to you