Foundation June 2022 Paper 1 Q19
19 The diagram shows parts of three regular polygons, A, B and C, meeting at a point.

Diagram NOT accurately drawn
Polygon B has \(n\) sides.
Work out the value of \(n\).
(4)
| Scheme | Marks |
|---|---|
| \(7x + 3x + 8x = 360\) oe | M1 |
| (\(x\) =) 360 ÷ 18 (= 20) | M1 |
360 ÷ (180 – 7 × “20”) oe or 360 ÷ (180 – “140”) \(\dfrac{(n - 2) \times 180}{n} = 7 \times \text{``}{20}\text{''}\) oe or 360 ÷ 40 | M1 |
| 9 | A1 |
| (4) | |
| (4 marks) |
Notes
M1: for 360 ÷ exterior angle
M2 for \(7x = 140\)
(140 can be on diagram)