Higher June 2023 Unit 1 Q4
4.
(a) Line \(AB\) is shown below.
Using only a ruler and a pair of compasses, construct an angle of 60° at point \(B\). [1]
Using only a ruler and a pair of compasses, construct an angle of 60° at point \(B\). [1]

(b) \(R\) is a point on the line \(LM\).
Using only a ruler and a pair of compasses, construct an angle of 90° at point \(R\). [1]
Using only a ruler and a pair of compasses, construct an angle of 90° at point \(R\). [1]

(c) Using only a ruler and a pair of compasses, construct a perpendicular line from the point \(P\) to the line \(XY\). [2]

| Scheme | Marks | Comments |
|---|---|---|
| Correct construction of 60° | B1 | Must be at point \(B\). Correct construction arcs (two or three) must be seen (initial and secondary). B0 if 60° and 30° drawn. Ignore additional lines provided intended 60° is clear (e.g any triangle, including equilateral \(ABC\)). For example: ![]() |
| Scheme | Marks | Comments |
|---|---|---|
| Correct construction of 90° | B1 | Must be at point \(R\) above or below \(LM\). Correct construction arcs (initial and secondary) must be seen. |
| Scheme | Marks | Comments |
|---|---|---|
| All correct construction arcs shown | M1 | Arc, centre P, intersecting \(XY\) at two points. (\(X\) may be one of the points with no arc seen at point \(X\).) [Note to markers: These arcs may be identified by the fact that they will ‘cross the line \(XY\) at an acute angle’. Arcs ‘crossing the line at 90°’ is evidence of an inappropriate method.] AND Intersecting arcs (equal radii) using the above two points as centres. Ignore line extended above \(XY\) for M1. |
| Line drawn | A1 | Ignore line extended above \(XY\) for M1A1. |
Alternative method
| Scheme | Marks | Comments |
|---|---|---|
| (Using the properties of a kite.) All correct construction arcs shown. | M1 | Intersecting arcs whose centres are any two points on the line XY and respective radii equal in length to the distance from the points to the point P. [Note to markers: The arcs will always intersect at a point that is a ‘reflection of point P’ in the line XY.] |
| Line drawn | A1 |
