Foundation June 2018 Paper 1 Q17
17. In the diagram, ABC is a triangle.
BC is parallel to DEF.
AEB and AFC are straight lines.

Diagram not drawn to scale
Show that \(x = 33^\circ\).
You must give a reason for each step of your working. [4]
| Scheme | Marks | Comments |
|---|---|---|
| Answers may be seen on the diagram; it must be clear from description or reasoning which angles are being calculated or used Alternative method for first 2 marks: | ||
| Angle AEF or Angle DEB = 93° (Angles on a straight line (sum to 180)) | B1 | Angle BEF = 87° (Vertically opposite angles (are equal)) |
| Angle AFE = 54° (Corresponding angles (are equal)) or Angle ABC = 93° (Corresponding angles (are equal) or alternate angles (are equal)) | B1 | Angle ABC = 93° (Interior angles (sum to 180)) |
| (\(x\) = ) 180° – 93° – 54° = 33° (Angles in a triangle (sum to 180)) | B1 | or equivalent e.g. 93 + 33 + 54 = 180 |
| A correct reason linked to a correct statement | B1 | |
| (4) |
Alternative
Alternative method 1: Assuming \(x = 33^\circ\):
| Scheme | Marks | Comments |
|---|---|---|
| Angle ABC = 180° – 33° – 54° = 93° (Angles in a triangle (sum to 180)) | B1 | |
| Angle AEF or Angle DEB = 93° (Angles on a straight line (sum to 180)) | B1 | |
| Angle ABC = Angle AEF (Corresponding angles (are equal)) or Angle ABC = Angle DEB or (Alternate angles (are equal)) | B1 | |
| A correct reason linked to a correct statement | B1 |
Alternative method 2: Assuming \(x = 33^\circ\):
| Scheme | Marks | Comments |
|---|---|---|
| Angle AFE = 54° (Corresponding angles (are equal)) | B1 | |
| Angle AEF = 180° – 33° – 54° = 93° (Angles in a triangle (sum to 180)) | B1 | |
| 93 + 87 = 180 (Angles on a straight line (sum to 180)) | B1 | |
| A correct reason linked to a correct statement | B1 |
Alternative method 3:
| Scheme | Marks | Comments |
|---|---|---|
| Angle AFE = 54° (Corresponding angles (are equal)) | B1 | |
| \(x + 54 = 87\) (Exterior angle (is equal to the sum of the two opposite interior angles)) | B1 | |
| \(x = 87 - 54 = 33\) | B1 | |
| A correct reason linked to a correct statement | B1 |