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\r\n Thales theorem is a special case of the inscribed angle theorem. It states that the angle subtended by a diameter of a circle on any point on the circumference of the circle is\r\n always a right angle (i.e. \\(90^o\\)).\r\n
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\r\n This MagicGraph provides a visually interactive illustration of the Thales theorem.
\r\n Points \\(A\\), \\(B\\) and \\(C\\) are three points on the circumference of the circle with center at \\(O\\). Points \\(A\\) and \\(B\\) can be moved on the circumference of the circle while point \\(C\\) always remains diagonally opposite to point \\(B\\) (i.e. \\(BC\\) is a diameter of the circle).
\r\n The angle 'a' is the inscribed angle by arc \\(BC\\) at point \\(A\\) while the angle 'b' is the central angle subtended by arc \\(BC\\) at the center \\(O\\) of the circle.
\r\n No matter where you place points \\(A\\) and \\(B\\) on the circumference of the circle, you will notice that the angle inscribed by arc \\(BC\\) at point \\(A\\) is always \\(90^o\\).\r\n