Higher November 2018 Unit 1 Q7
7. In this question, you will be assessed on the quality of your organisation, communication and accuracy in writing.
\(A\), \(B\) and \(C\) are points on the circumference of a circle with centre \(O\).
\(A\hat{C}B = 74^\circ\).
Diagram not drawn to scale
Calculate the value of \(x\).
You must state any angle property of a circle that you use.
You must show all your working. [4 + 2 OCW]
| Scheme | Marks | Comments |
|---|---|---|
| AOB = 148(°) | B1 | May be seen on the diagram. Do not accept 148 unless unambiguously associated with angle AOB (stated, or on diagram, or used for M1). |
| Angle subtended by an arc at the centre of a circle is twice the angle subtended at the circumference. | E1 | Dependent on 2 × 74 (= 148) seen. Accept any unambiguous wording. E0 for simply stating ‘twice 74’. |
| \(x = \dfrac{180 - 148}{2}\) | M1 | FT ‘their derived or stated angle AOB’. NOT 74°. x = 90 – 74 is B1E0M1 (E1 if a full and accurate explanation is given.) |
| = 16 | A1 | Unsupported (x =) 16 gains B1E0M1A1. |
| Organisation and Communication. | OC1 | For OC1, candidates will be expected to:
|
| Accuracy of writing. | W1 | For W1, candidates will be expected to:
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