Inscribed angle (other)
Overview
Important
Inscribed angles can have special properties depending on where their vertex and sides are located. For example, if the inscribed angle subtends a diameter, it is always a right angle (Thales' theorem). If two inscribed angles subtend the same arc, they are equal. These 'other' cases extend the basic inscribed angle theorem to more situations.
Important properties
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An inscribed angle subtending a diameter is a right angle (Thales' theorem).
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Inscribed angles subtending the same arc are equal.
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If the inscribed angle's sides are diameters, the angle is 180°.
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If the inscribed angle subtends a semicircle, it is a right angle.