Commensurable and incommensurable quantities

Two quantities are said to be commensurable if their ratio can be expressed as the ratio of two integers.

Examples:

a) Ratio of Rs.20 to Rs. 48

Rs.20, Rs.48 are commensurable.

, 4 are incommensurable

(Ratio cannot be expressed in terms of integers,

c) Ratio of the side of square to its diagonal.

Hence side of a square and its diagonal are not commensurable.