Higher June 2017 Unit 2 Q5
5. Construct an accurate drawing of triangle ABC, where AB = 7 cm, \(A\hat{B}C = 90^\circ\) and \(B\hat{A}C = 60^\circ\).
Use only a ruler and a pair of compasses.
The side AB has been drawn for you.
You must show your construction arcs. [3]

On screen this diagram may not be shown at actual size. To draw on it, use the question paper (PDF) printed at 100%.
| Scheme | Marks | Comments |
|---|---|---|
| Correct construction of 90° at point B. | B2 | With sight of accurate ‘method arcs’. e.g . (i) AB extended with arcs either side of B on extended line AB (or line AB extended by 7cm) AND arcs above or below point B). (ii) construction of 60°, 120° and a bisection. B1 for complete method but line not drawn. |
| Correct construction of angle BAC = 60°. | B1 | With sight of accurate ‘method arcs’ and line drawn. If all three marks gained but triangle not completed penalise −1 mark. (Treat reversal of angles as a misread.) |