Foundation January 2019 Paper 2 Q13

EdexcelFoundationCurrent spec5 marksAngles (Including Parallel Lines)

Triangle ABD with AB = DB; C on line DE with BC drawn. Angle ABD = 48°, angle BCE = 68°, reflex angle ADC = 243°, angle DBC marked y

Diagram NOT accurately drawn

\(ABD\) is an isosceles triangle with \(AB = DB\).
\(DCE\) is a straight line.

Angle \(ABD\) = 48°
Angle \(BCE\) = 68°
Reflex angle \(ADC\) = 243°

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

(5)

Mark scheme

Scheme	Marks
Angle \(BCD\) = 180 – 68 (= 112) or angle \(BAD\) (or \(BDA\)) = (180 – 48) ÷ 2 (= 66)	M1
angle \(BDC\) = 360 – 243 – “66” (= 51) or angle \(ADC\) = 360 – 243 (= 117)	M1
e.g. 68 – “51” (= 17) or 180 – (180 – 68) – “51” or 360 – “117” – “66” – (180 – 68) – 48	M1
	B1
17 with reasons	A1
	(5)
	(5 marks)

Notes

M1: Could be seen on diagram

M1: for a complete method

B1: dep on M1 for any one correct appropriate reason

A1: for correct answer with full reasons
E.g.
Base angles of an isosceles triangle are equal
Angles in a triangle sum to 180°
Angles at a point add up to 360° / full turn
Angles on a straight line sum to 180° or exterior angle equals the sum of interior opposite angles
Angles in a quadrilateral add up to 360°