How do you simplify the square root of 18 without using a calculator?

Surds can be simplified if the number in the square root has a square number as a factor. It is also worth remembering that SQRT(ab) = SQRT(a) x SQRT(b). So if you combine these two points, lets look at how we can simplify the square root of 18.

A factor of 18 that is a square number is 9. Therefore SQRT(18) = SQRT(9) x SQRT(2). The square root of 9 is 3, so we can now write our final answer as SQRT(18) = 3 x SQRT(2). To check you’ve understood this, you might like to have a go at simplifying these two surds. A) SQRT(20)  B) SQRT(32)

Answered by Richard B. Maths tutor

4363 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Factorise fully 27x^2 - 3


Solve the simultaneous equation: 2x +y =18; x-y=6. (3)


Expand 2a (4 + a)


Solve the equation [(3x + 3)/2x] + 2x - 1 = -3


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences