Moderate -0.8 This is a straightforward application of the cosine rule with all required values given directly. It requires only substituting into a standard formula and calculating, making it easier than average with no problem-solving or multi-step reasoning needed.
\(76.(\ldots)\) or \(204.(\ldots)\) (radians) or \(64.(\ldots)\) (grad); NB \(6.76\cos72\) or \(2.08(8954882\ldots)\) scores M1M0
\(8.7(2\ldots)\)
A1
if M0M0, B3 for \(8.72\) or better if unsupported or if \(8.7(2\ldots)\) if obtained from other valid method
Total: [3]
$5.9^2 + 8.5^2 - 2 \times 5.9 \times 8.5 \times \cos 72$ | M1 |
$107 - 31$ or better | M1 | $76.(\ldots)$ or $204.(\ldots)$ (radians) or $64.(\ldots)$ (grad); NB $6.76\cos72$ or $2.08(8954882\ldots)$ scores M1M0
$8.7(2\ldots)$ | A1 | if M0M0, B3 for $8.72$ or better if unsupported or if $8.7(2\ldots)$ if obtained from other valid method
**Total: [3]**
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\includegraphics{figure_5}
Fig. 5 shows triangle ABC, where angle ABC = $72°$, AB = $5.9$ cm and BC = $8.5$ cm. Calculate the length of AC. [3]
\hfill \mbox{\textit{OCR MEI C2 2014 Q5 [3]}}