Question

Check whether √81 is a surd_____ *
​

Answer 1

√81 is not a surd.

Reason why?

√81 is equals to 9 or -9.

9 and -9 are rational numbers. Surds are never rational numbers.

Surds are always irrational numbers.

What are irrational numbers?

Numbers whose exact value can't be obtained are and cannot be written in the form of p/q where q ≠ 0, are known as irrational numbers.

Examples → √2, √3, √5 etc.

More about this topic:-

• All Surds are irrational numbers, but all irrational numbers aren't Surds. For example $\rm \pi , \ e^2 \ etc.$
• aᵇ=c can be written as $\rm\sqrt[b]{c}=a$
• $\rm\sqrt[2]{a} = \sqrt{a}$