Find which of the variables x, y, z and u represent rational numbers and which irrational numbers:

(i) x2 = 5 (ii) y2 = 9


(iii) z2 = .04 (iv)

(i) x2 = 5


On taking square root on both sides, we get


x = ± √5


So, x is an irrational number.


(ii) y2 = 9


On taking square root on both sides, we get


y = ± 3


So, y is a rational number.


(iii) z2 = .04


On taking square root on both sides, we get


z = ± 0.2


So, z is a rational number.



On taking square root on both sides, we get



So, u is an irrational number because 17 is irrational.


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