June 2025 Paper 2 Q3
3 The diagram shows triangle ABC.
AB = 4.7 cm, AC = 6.9 cm and BC = 11.2 cm.
Find the size of angle CAB. Give your answer correct to 3 significant figures. [2]
| Scheme | Marks | AO |
|---|---|---|
| \(\cos \text{CAB} = \dfrac{4.7^2 + 6.9^2 - 11.2^2}{2\times 4.7\times 6.9}\) oe soi | M1 | 1.1a |
| 2.60 or 149 cao | A1 | 1.1 |
| [2] |
Notes
M1: may be implied by correct answer to 3 or more significant figures
may see \(\dfrac{-55.74}{64.86}\) or \(-0.859(389\ldots)\)
NB 2.60487074… or 149.2480998..
A1: must be to 3 s.f. ; ignore incorrect units