Higher June 2023 Paper 5 Q17
17 A rhombus is drawn on a coordinate grid.
One diagonal of the rhombus has equation \(y = \frac{1}{2}x + 3\).
The other diagonal passes through the point (1, 7).
Find the equation of the other diagonal of the rhombus.
Give your answer in the form \(y = mx + c\). [4]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| [\(y\) =] \(-2x + 9\) final answer | 4 | B2 for grad = – 2 soi or M1 for diagonals cross at 90° soi M1 for substituting (1, 7) into \(y\) = (their m)\(x + c\) oe soi | Accept \(\frac{-2}{1}\) for all marks B2 implied by e.g. [\(y\) =] \(-2x + c\) oe M1 could be on a diagram e.g. \(y - 7\) = (their m)\((x - 1)\) Answer [\(y\) =] ½ \(x + 6.5\) implies M1 M1 soi by answer with their gradient e.g. \(y = 2x + 5\) satisfies (1, 7) so gets M1 |