CBSE Notes, Lectures

CBSE - Mathematics - Number Systems

Number Systems

NCERT Exercise Exercise 1.5

Recall, π is defined as the ratio of the circumference (say c) of a circle to its diameter (say d). That is, π = c/d. This seems to contradict the fact that π is irrational. How will you resolve this contradiction?

There is no contradiction. When we measure a value with a scale, we only obtain an approximate value. We never obtain an exact value. Therefore, we may not realise that either c or d is irrational. The value of π is almost equal to 22/7 or 3.142857... Therefore, the fraction  c/d  is irrational. Hence, π is irrational.

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