Answer:

A rational number is any number that can be expressed as a ratio of two integers (hence the name "rational"). ... For example, 1.5 is rational since it can be written as 3/2, 6/4, 9/6 or another fraction or two integers. Pi (π) is irrational since it cannot be written as a fraction.

Given, dr/dt = 0.1 cm/sec find dA/dt = ?

we know area of circle I.e Q = nr2

= dA/dt = (2nr) dr/dt

= dA/dt = 2nr×0.1 = 0.2nr

now at r= 5/11

= dA/dt = 0.2n (5/11) = 0.2 (22/7)(5/11)

= dA/dt = 2/7 = 0.285 cm2/sec