ACT Preparation / Unit 14 ACT 1309 short lesson, about 20 seconds
The Inscribed Angle
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The idea
An inscribed angle has its vertex on the circle and its sides as chords. It equals half of its intercepted arc, so half the central angle on the same arc.
In practice
An arc of 100° gives a central angle of 100° and an inscribed angle of 50°.
Where people slip
An inscribed angle on a diameter intercepts 180°, so it is always 90°.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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