Circle Theorems

Front

Subtended Angle

Back

The angle outside of the triangle is the double of the angle inside the triangle.

Front

Opposite angles in a cyclic quadrilateral

Back

opposite angles in a cyclic quadrilateral add up to 180°

Front

Angles in semi-circle

Back

Angle subtended in a semi circle is a right angle

Front

Angles in a the same segment

Back

Angles in a same segment are equal