Mathematics for IGCSE & O level - Circle Theorems (Section 2 - No. 41)
In a circle, which relationships can be used to find angle measures?
Angle at the center is twice angle at circumference.
Angles in the same segment are equal.
Opposite angles in a cyclic quadrilateral are supplementary.
The angle between the tangent and chord is equal to the angle in the alternate segment.
Giải thích
These are the basic circle theorems for angle measurements.