4MA1/1HR Jan 2022, Question 22: Calculating with Bounds
Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 1HR (Higher) · Calculator · 4 marks
اقرأ هذا الحل مشروحاً بالعربي ←
The question, in short
Using triangle ABC with c = 11.5, x = 80 and y = 75, each rounded, find the upper bound of side b, showing working and giving 3 significant figures.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Solution · 4 marks
- 1Bounds: c up to 11.55, x down to 79.5, y down to 74.5
- 2Angle B = 180 − x − y is largest when x and y are smallest: 180 − 79.5 − 74.5 = 26°
- 3Sine rule: b = c × sin B ÷ sin y = 11.55 × sin 26° ÷ sin 74.5°
- 4b = 5.254…, so the upper bound is 5.25
Answer5.25
Stuck on a step? Read the free lesson: Calculating with Bounds
Practise more calculating with bounds questions
Real 4MA1 past-paper questions, marked on your working like the exam, with a worked solution for every part.
Practise free on LemmaraMore past-paper questions on calculating with bounds
Also searched as: 4MA1 1HR January 2022 · 4MA1/1HR · 4ma1 jan22 1hr · question 22.
Lemmara is an independent study tool, not affiliated with or endorsed by Pearson Edexcel. The worked solutions are Lemmara’s own.