Question

Which numbers are irrational
√196
√80
√18
√12
7\18

Answer 1

7/18 because its a fraction and it does not have a rational sign on it

Answer 2

sqrt(80)

sqrt(18)

sqrt(12)

Explanation:

sqrt(196) = 14 which is rational.

7/18 is a fraction. There is nothing the matter with it. It is rational.

sqrt(80) = sqrt(16 * 5) = sqrt(4*4* 5) = 4 sqrt(5) which is irrational.

sqrt(18) = sqrt(9*2) = sqrt(3*3*2) = 3*sqrt(2) which is irrational.

sqrt(12) = 2sqrt(3) which is irrational

Rule: if there is anything left under the root sign then the starting number is irrational.