Higher November 2017 Paper 4 Q17
17 ABC and ACD are triangles.
Not to scale
(a) Show that AC = 13.0 cm, correct to 3 significant figures. [4]
(b) Calculate BC.
........................................ cm [3]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| Attempt to use the cosine formula | M1 | Evidenced by the formula e.g. \(a^2 = b^2 + c^2 - 2bc\cos A\) or better | |
| \([\ldots]^2 = 14^2 + 18^2 - 2 \times 14 \times 18 \cos 46\) oe | M2 | ||
| or | |||
| cosine formula with at most 2 errors or correct cosine formula starting \(\cos [\ldots] = \dfrac{14^2 + 18^2 - [\ldots]^2}{2 \times 18 \times 14}\) | M1 | ||
| 13.03… | A1 | ||
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 35.48 to 35.6 | 3 | B1 for 180 − 78 − 81 or 21 M1 for \(\dfrac{13.0\ldots}{\sin \textit{their } 21} = \dfrac{[\ldots]}{\sin 78}\) oe or better | could be on diagram accept any correct method |