Question 2
Ratio, Percentages and RatesThe radius of a circle is given as 5cm subject to an error of 0.1cm. What is the percentage error in the area of the circle?
- A.1/25
- B.1/4
- C.4
- D.25
Show the answer and explanation
Answer: C (4)
Explanation
The radius error is 0.1/5 = 2%. Since the area depends on r2, its error is about 2 × 2% = 4% (exactly, (5.12 − 52)/52 = 4.04%).