Higher January 2020 Paper 1R Q14

EdexcelHigherCurrent spec4 marksCircle Theorems

Circle centre O with points A, B and C on the circle; chords BA and BC with angle ABC = 38°; radii OA and OC

Diagram NOT accurately drawn

\(A\), \(B\) and \(C\) are points on a circle, centre \(O\).

Angle \(ABC = 38^\circ\)

Work out the size of angle \(OAC\).
Give a reason for each stage of your working.

(4)

Mark scheme

Scheme	Marks
(\(AOC\) =) 38 × 2 (= 76)	M1
52	A1
	B2
	(4)
	(4 marks)

Notes

B2: (dep on M1) for all reasons relevant to their method – underlined words must be seen.
angle at the centre is 2 × (double) angle at circumference / angle at circumference is ½ angle at centre
angles in a triangle add to 180° or angles in a triangle add to 180°
base angles in an isosceles triangle (are equal)
If not B2 then award B1 (dep on M1) for a correct circle theorem