# Exam-Style Questions on Approximation

## Problems on Approximation adapted from questions set in previous exams.

### 1.

GCSE Higher

Ayden is marking out the pitch for a ball game in a large field.

He measures the length of the pitch, which needs to be at least ten metres long, by pacing. Ayden knows that his stride length is 0.7 metres, rounded to the nearest tenth of a metre. Find the minimum number of strides Ayden will need to take to guarantee that the pitch is no shorter than ten metres long.

### 2.

GCSE Higher

(a) Use your calculator to evaluate the following expression to five significant figures.

$$\sqrt[3]{8005} + \sqrt{98.5} \div 5.02$$

(b) Show how, by using approximations, your answer to part (a) is reasonable.

### 3.

GCSE Higher

Minerva's Revenge, the longest rollercoaster in the Funville Theme Park, takes 95 seconds (to the nearest 5 seconds) to complete one circuit of the 2280 metre long track.

(a) Mr Finklestein assumes that the track has been measured to the nearest 10m. What is the greatest possible speed of the rollercoaster train if his assumption is correct?

(b) Mr Finklestein finds out that in fact the track was measured to the nearest 5m. With this new information recalculate the greatest possible speed.

(c) Comment on the effect this new information had on the results of the calculations.

### 4.

IB Studies
$$A = \frac{(\sin(x) + y)(\cos(x) - y)}{w^2 + 4z}$$

If $$w = 12, x = 45°, y = \frac12 \text{and } z = 14$$ calculate:

(a) the exact value of $$A$$;

(b) the value of $$A$$ to two significant figures;

(c) the value of $$A$$ to three decimal places;

Rosie estimates the value of $$A$$ to be 0.0012.

(d) Calculate the percentage error in Rosie's estimate.

The exam-style questions appearing on this site are based on those set in previous examinations (or sample assessment papers for future examinations) by the major examination boards. The wording, diagrams and figures used in these questions have been changed from the originals so that students can have fresh, relevant problem solving practice even if they have previously worked through the related exam paper.

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