Foundation November 2021 Paper 1 Q31
31 Here is a right-angled triangle.
Not drawn accurately
Use trigonometry to work out the value of \(x\). [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(\sin 30 = \dfrac{x}{10}\) or \((x =)\ 10 \sin 30\) | M1 | oe eg \(\dfrac{x}{\sin 30} = \dfrac{10}{\sin 90}\) |
| \(\sin 30 = 0.5\) | M1 | oe may be seen in a table \(0.5 = \dfrac{x}{10}\) oe scores M1M1 |
| 5 | A1 | |
| Alternative method 2 | ||
| Correct trigonometric method to show that the length of the missing side is \(5\sqrt{3}\) | M1 | oe |
| \(\sqrt{(5\sqrt{3})^2 + x^2} = 10\) | M1dep | oe |
| 5 | A1 | |
Additional guidance
Accept use of cos 60 instead of sin 30