1MA0 Foundation November 2015 Paper 1 Q20

*20

Diagram NOT accurately drawn

\(ABCD\) and \(EFG\) are parallel lines.
\(BC = CF\)
Angle \(BFE = 70^\circ\)

Work out the size of the angle marked \(x\).
Give reasons for each stage of your working. (4)

Mark scheme

Answer	Mark	Notes
\(40^\circ\)	4	M1 for angle \(FBC = 70\) or \(CFG = x\) or \(ABF = 110\) may be seen in diagram M1 for angle \(CBF = BFC = 70\) or \(90 - \tfrac{1}{2}x\) may be seen in diagram A1 for 40 supported by working C1 (dep on M2) for full reasons linked to appropriate working, eg alternate angles are equal; allied angles / co-interior angles add up to \(180^\circ\); base angles of an isosceles triangle are equal, angles on a straight line add up to \(180^\circ\), angles in a triangle add up to \(180^\circ\)