Higher November 2024 Paper 2 Q9
9 The diagram shows two congruent regular 9-sided polygons.
\(ABCD\) is a quadrilateral.
Show that \(ABCD\) is not a square. (3)
| Answer | Mark | Mark scheme |
|---|---|---|
| shown | M1 | for method to find the interior angle eg \((9 - 2) \times 180 \div 9\ (= 140)\) or exterior angle eg \(360 \div 9\ (= 40)\) of a regular nonagon |
| M1 | for a complete method to find the interior angle \(ABC\), eg \(360 - \text{``}140\text{''} - \text{``}140\text{''}\ (= 80)\) or \(\text{``}40\text{''} \times 2\ (= 80)\) or finds the angle sum assuming a square, eg \(90 + \text{``}140\text{''} + \text{``}140\text{''}\ (= 370)\) | |
| A1 | for complete solution with correct conclusion, eg interior angle of a square is 90, not 80 or angles around a point sum to 360 not 370 |
Additional guidance
Angles may be shown on the diagram
Any angle labelled correctly as 140 or 40 and not contradicted scores this mark