Angles and circles
This page covers the following topics:
The angle subtended at the centre of a circle is twice the angle subtended at the circumference.
The angle at the circumference of a semicircle is 90°.
Angles in the same segment are equal.
The sum of opposite angles in a cyclic quadrilateral is 180°.
A tangent to a circle is always perpendicular to the radius of that circle.
End of page