Higher November 2021 Paper 1 Q4
4 The diagram shows the front of a wooden door with a semicircular glass window.
Diagram NOT accurately drawn
Julie wants to apply 2 coats of wood varnish to the front of the door, shown shaded in the diagram.
250 millilitres of wood varnish covers 4 m2 of the wood.
Work out how many millilitres of wood varnish Julie will need.
Give your answer correct to the nearest millilitre.
(5)
| Scheme | Marks |
|---|---|
| 2 × 0.75 (= 1.5) oe or 2 × 0.75 × 2 (= 3) oe | M1 |
\(\pi \times (0.5 \div 2)^2\ (= 0.1963)\) or \(\dfrac{1}{2} \times \pi \times (0.5 \div 2)^2\ (= 0.09817)\) | M1 |
| “1.5” – “0.09817” (= 1.4018…) or “3” – “0.1963” (= 2.8036…) | M1 |
| “1.4018” × 2 × 250 ÷ 4 (= 175.228…) or “2.8036” × 250 ÷ 4 (= 175.228…) or “1.4018” × 250 ÷ 4 (= 87.6…) | M1 |
| Correct answer scores full marks (unless from obvious incorrect working) Answer: 175 | A1 |
| (5) | |
| (5 marks) |
Notes
M1: for area of rectangle
M1: for area of circle or area of semicircle
M1: or for 87 – 88
A1: Allow 175 – 176