Help PLEASE I don’t understand or know how to do this

Square root of 27 cannot be simplified

Step-by-step explanation:

ok here I think that you have to find the square root of the numbers in this case you can get the square root of these numbers using a four-figure mathematical log table then you can use numbers like 123456789 to see if they go into that number that's what I think

i think it would be 42cm