OCR MEI C2 — Question 8 5 marks

Exam BoardOCR MEI
ModuleC2 (Core Mathematics 2)
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicSine and Cosine Rules
TypeBasic cosine rule application
DifficultyEasy -1.2 This is a straightforward single-step application of the cosine rule with all required values given directly. It requires only substitution into the formula a² = b² + c² - 2bc cos A and basic calculator work, making it easier than average with no problem-solving or multi-step reasoning required.
Spec1.05b Sine and cosine rules: including ambiguous case
8 In the triangle \(\mathrm { ABC } , \mathrm { AB } = 5 \mathrm {~cm} , \mathrm { AC } = 6 \mathrm {~cm}\) and angle \(\mathrm { BAC } = 110 ^ { \circ }\).
Find the length of the side BC .
Question 8:
AnswerMarks Guidance
AnswerMarks Guidance
\(BC^2 = 5^2 + 6^2 - 2\times5\times6\times\cos110°\)M1
\(= 61 + 20.52 = 81.52\)A1, B1, A1 For getting negative for \(\cos110°\)
\(\Rightarrow BC = 9.03\) cmA1 [5] 
## Question 8:

| Answer | Marks | Guidance |
|--------|-------|----------|
| $BC^2 = 5^2 + 6^2 - 2\times5\times6\times\cos110°$ | M1 | |
| $= 61 + 20.52 = 81.52$ | A1, B1, A1 | For getting negative for $\cos110°$ |
| $\Rightarrow BC = 9.03$ cm | A1 | **[5]** |

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8 In the triangle $\mathrm { ABC } , \mathrm { AB } = 5 \mathrm {~cm} , \mathrm { AC } = 6 \mathrm {~cm}$ and angle $\mathrm { BAC } = 110 ^ { \circ }$.\\
Find the length of the side BC .

\hfill \mbox{\textit{OCR MEI C2  Q8 [5]}}
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