Foundation November 2018 Paper 3 Q13
13 A small square has length \(x\) cm
A large square has length 15 cm
Not drawn accurately
The area of the small square is \(\dfrac{1}{9}\) of the area of the large square.
Work out the value of \(x\). [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(15^2\) or 225 | M1 | |
| their \(225 \div 9\) or 25 | M1dep | oe |
| 5 | A1 | |
| Alternative method 2 | ||
| \(\sqrt{9}\) or 3 or \(\sqrt{\dfrac{1}{9}}\) or \(\dfrac{1}{3}\) | M1 | |
| \(15 \div\) their 3 or \(15 \times\) their \(\dfrac{1}{3}\) | M1dep | oe |
| 5 | A1 | |
| Alternative method 3 | ||
| \(\left(\dfrac{x}{15}\right)^2 = \dfrac{1}{9}\) | M1 | oe |
| \((x^2 =)\ \dfrac{15^2}{9}\) or 25 | M1dep | oe |
| 5 | A1 | |
Additional guidance
| \(3x = 15\) | M1M1 |
| \(5^2 = 25\) without 5 on answer line | M1M1A0 |
| 1 : 3 or 3 : 1 | M1 |