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Re: Triangle inscribed in a semicircle [#permalink]
02 May 2008, 19:53
This is my interpretation. If you consider a semicircle, the central angle is 180 degrees.
And we know that an inscribed angle is half the central angle so :
The triangle whose angle is 90 is 1/2 the central angle which is 180.I am not sure why this is the case exactly but my guess is that the central angle is a factor of r and an angle inscribed on the circle is a factor of the diameter = 2r and therefore the angle will decrease by a factor of 1/2.