IGCSE Mathematics Extended E4.7.1 Calculate unknown angles and give explanations using the following Question Bank

• Calculate unknown angles and give explanations using the following geometrical properties of circles: • angle in a semicircle = 90° • angle between tangent and radius = 90° • angle at the centre is twice the angle at the circumference • angles in the same segment are equal • opposite angles of a cyclic quadrilateral sum to 180° (supplementary) • alternate segment theorem. Candidates are expected to use the geometrical properties listed in the syllabus when giving reasons for answers.