Higher November 2018 Paper 3 Q6
6 \(ABC\) is a right-angled triangle.
\(AC = 14\) cm.
Angle \(C = 90^\circ\)
size of angle \(B\) : size of angle \(A\) = 3 : 2
Work out the length of \(AB\).
Give your answer correct to 3 significant figures. (4)
| Answer | Mark | Mark scheme |
|---|---|---|
| 17.3 | P1 | for full process to find either angle eg \((180 - 90) \div (2 + 3) \times 2\) or for 36 or 54 seen as an angle |
| P1 | for a correct equation using trigonometry eg \(\cos [A] = 14 \div AB\) | |
| P1 | (dep previous P mark) for rearranging their trigonometry equation to make \(AB\) the subject eg (\(AB =\)) \(\text{``}14 \div \cos 36\text{''}\) | |
| A1 | for an answer in the range 17.3 to 17.4 |
Additional guidance
May be seen on diagram
Condone correct values if incorrectly placed.
This must be shown as an equation with all four elements (eg cos, [\(A\)], 14, \(AB\)) present.
[\(A\)] could be 36 or any angle clearly and unambiguously identified as \(A\).
This also applies to [\(B\)] with Sine.
If an answer is shown in the range in working and then incorrectly rounded award full marks.