Question

what are the seven circle theorems?

Answer 1

The seven circle theorems are as follows:

• The angle at the center is twice the angle at the circumference of a circle.
• Angles in a semicircle is $90°$.
• Angles in the same segment are equal.
• In a cyclic quadrilateral, the sum of opposite angles is $180°$.
• Radius to a tangent: The angle between a tangent and a radius is $90°$.
• Tangents from a point to a circle: The lengths of the two tangents from a point to a circle are equal.
• Alternate segment theorem: The angle between the tangent and the chord at a point of contact is equal to the angle in the alternate segment.