MathematicsCode 4029
Circle theorems I
What this topic asks you to be able to do
- Work out unknown angles and give reasons, using these circle properties: the angle in a semicircle = 90°; the angle between a tangent and a radius = 90°; the angle at the centre is double the angle at the circumference; in the same segment, the angles are equal; in a cyclic quadrilateral, opposite angles add up to 180° (supplementary); the alternate segment theorem. Reasons for answers should quote the geometrical properties set out in this course.