Prisms: WJEC GCSE Numeracy Higher November 2018 Unit 2 Q4

Numeracy Higher November 2018 Unit 2 Q4

WJECHigherCurrent spec8 marksPrisms Pythagoras Units & Time

(a) In this part of the question, you will be assessed on the quality of your organisation, communication and accuracy in writing.

Luned’s tent is in the shape of a triangular prism.
The cross-section of her tent is an isosceles triangle.

She noted a few measurements on a diagram of her tent, as shown below.

Diagram not drawn to scale

Calculate the volume of Luned’s tent.
Give your answer in m³.
You must show all your working. [5 + 2 OCW]

Volume of Luned’s tent is …………… m³

(b) Which of the following is equal to 0·2 m³?
Circle your answer. [1]

20 cm³ 200 cm³ 2000 cm³ 200 000 cm³ 2 000 000 cm³

From the formula list: Volume of prism = area of cross-section × length

Mark scheme (a)

Scheme	Marks	Comments
(Perpendicular height, h) (h² =) 1.8² – 0.7² or 1.8² = h² + 0.7²	M1
h² = 2.75 or (h =) √2.75 (Perpendicular height is) h = 1.658(...m) or 1.66 (m) or 1.7 (m)	A1 A1	Accept √11 ⁄ 2 Accept √11 ⁄ 2 Do not accept truncation to 1.6(m) or 1.65 (m) (But FT allowed) FT from M1, A0 for the correctly evaluated square root of ‘their 2.75’ provided ‘their answer’ <1.8 (m)
(Volume of Luned’s tent =) ½ × (0.7+0.7) × 1.658.... × 2.5 or equivalent	M1	FT ‘their derived 1.658(....)’ provided ≠1.8 or ≠0.7
(Volume) Answer in the inclusive range 2.9 (m³) to 2.98(m³) or 3(.0m³)	A1	Check from correct working (in particular for an answer of 3(m³)) FT 1.6m or 1.65m to an answer in the range 2.8(m³) to 2.89(m³) FT from previous M1 awarded for a similar range
Organisation and communication	OC1	For OC1, candidates will be expected to: • present their response in a structured way • explain to the reader what they are doing at each step of their response • lay out their explanations and working in a way that is clear and logical • write a conclusion that draws together their results and explains what their answer means
Writing	W1	For W1, candidates will be expected to: • show all their working • make few, if any, errors in spelling, punctuation and grammar • use correct mathematical form in their working • use appropriate terminology, units, etc.