or mark on cf axis from using = 52 A M1 (dep) 792000 816000 3 A1 for answer in the range 792000 816000 – – Total 8marks Working Answer Mark AO 12 a AO1 M1 for gradient eg. 2 = × 1 + or M1 for method to find c c = (x 1) y −2 – = + M1 found values of and substituted in = + y x m c y mx c 3x + 4y = 11 4 A1 b = or = AO1 M1 y m shown 2 A1 for conclusion from correct gradients 13 Scheme 1 (interior angle and angle and an angle in triangle Let be midpoint of ADC ADC) X DC (Angle =) = 108 M1 or for 108 seen as an interior angle DEA Angle or = (180 108)÷2 = 36 M1 EDA EAD – Angle or = 108 36 = 72 or M1 Angles may be seen on diagram ADC ACD – Angle = 108 2 × 36 (=36) or DAC – Angle = DAC Angle or = (108 2 × 36) ÷ 2 (=18) DAX CAX –
or mark on cf axis from using A = 52 M1 (dep) 792000 – 816000 3 A1 for answer in the range 792000 – 816000 Total 8marks Working Answer Mark AO 12 a AO1 M1 for gradient eg. 2 = × 1 + c or M1 for method to find c y −2 = (x – 1) y = x + M1 found values of m and c substituted in y = mx + c 3x + 4y = 11 4 A1 b y = or m = AO1 M1 shown 2 A1 for conclusion from correct gradients 13 Scheme 1 (interior angle and angle ADC and an angle in triangle ADC) Let X be midpoint of DC (Angle DEA =) = 108 M1 or for 108 seen as an interior angle Angle EDA or EAD = (180 – 108)÷2 = 36 M1 Angle ADC or ACD = 108 – 36 = 72 or Angle DAC = 108 – 2 × 36 (=36) or Angle DAC = Angle DAX or CAX = (108 – 2 × 36) ÷ 2 (=18) M1 Angles may be seen on diagram
igcse-9-1-maths-practice-paper-3-mark-scheme.docx