# Pi......From a Student's Perspective

Examiners in the HSC Advanced Mathematics (2 unit) course have commented that many students become confused when the constant π is used in calculations. What is it about π that causes problems? Students from an early age learn that π is the ratio of the circumference of a circle to its diameter and so this reinforces the geometrical interpretation of π. However, π can be involved in problems that have no connection with circles and this is when confusion in examination answers can arise. Some students convert an answer involving π into revolutions or degrees just because of the  connection of π to the geometry of a circle. Pi is a number, an irrational number, and should be treated like any other number in calculations. In the 2015 Mathematics examination question 15 c involved calculating the time when the volume of water in a pool first started to decrease given the rate of change of the volume. The answer was 2π seconds and many candidates lost marks by converting this into degrees.

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