Circle: Angles

Central Angle and Inscribed Angle

 

Central Angle and Inscribed Angle

 

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A central angle of a circle is an angle whose vertex is located at the center of the circle

Example: ∠AOB

 

An inscribed angle is an angle whose vertex is on a circle and whose sides each intersect the circle at another point

Example: ∠ACB

 

The measure of the central angle is double the measure of the inscribed angle intercepting the same arc

m∠AOB = 2 × m∠ACB

Two or more inscribed angles intercepting the same arc are equal

 

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m∠ACB = m∠ADB = m∠AEB 

Any inscribed angle whose endpoints are a diameter is a right angle, or 90°

 

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m∠ACB = 90°

 

Exercise

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(Next Lesson) Angles Outside of A Circle
Kembali ke Circle: Angles