Higher November 2020 Paper 2 Q20
20 \(AB\), \(BC\), \(CD\) and \(DE\) are four of the sides of a regular decagon.
Not drawn accurately
Work out the size of angle \(w\). [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(180 - \dfrac{360}{10}\) or \(180 - 36\) or \(1440 \div 10\) or 144 | M1 | oe eg \((10 - 2) \times 180 \div 10\) may be seen on diagram |
| \(\dfrac{540 - 3 \times \text{their } 144}{2}\) or \(\dfrac{540 - 432}{2}\) or \(\dfrac{108}{2}\) or \(360 - 90 -\) their \(144 - \dfrac{\text{their } 144}{2}\) or their \(144 - 90\) | M1dep | oe eg \(\dfrac{(5 - 2) \times 180 - 3 \times \text{their } 144}{2}\) |
| 54 | A1 |
Additional guidance
| \(540 \div 10 = 54\) | M0M0A0 |
| 144 worked out but not used | M1M0A0 |