What Is The Square Root Of 85?

10 Answers

Jackie Russell Profile
Jackie Russell answered
The square root of 85 is 9.22, or to be exact 9.21954445729289. If you are unsure about working out the square root of a number, visit NumberPlanet.com where the answer will be worked out for you quickly and easily.

The square of a number is that number multiplied by itself. For example, the square root of 100 is 10 because 10 x 10 = 100. The square root of 25 is 5 because 5 x 5=25.  Sometimes they are perfect, like in these examples but for the majority of the time they will not be whole ‘perfect numbers’, or integers, and there will be a series on numbers after the decimal, which is why a calculator is often needed to find the answer. 1, 4, 9, 16, 25, 36, 49, 64, 81, 100 are all ‘perfect squares’.

It is possible to find perfect squares or estimate squares without a calculator. First of all, you need to estimate and get as close as you can by finding two perfect square roots your number is between then divide your number by one of those square roots. Take the average of the result of step two and the root. Use the result of step two to repeat steps two and three until you have a number that is accurate enough for you.
Anonymous Profile
Anonymous answered
Liam Bandel Profile
Liam Bandel answered
9.22 (3 sig-fig)
Will Martin Profile
Will Martin answered
I don't want to type a wrong figure by mistake, so please go to csgnetwork.com to find the exact answer.
thanked the writer.
Anonymous commented
What if you don't have a calculator?

81 < 85 < 100
9^2 < 85 < 10^2
so you know the square root of 85 is between 9 and 10, and closer to 9 (since 85 is closer to 81 than it is to 100).

So, trial and error... Since you only need to the tenth, you should start with 9.1 and work up. (since 85 is SO CLOSE to 81, I would guess it's pretty low.)

(9.1)^2 = (9.1)(9.1) = 82.81
(9.2)^2 = 84.64

9.2 is as close to 85 as you're going to get, so that would be my estimate.

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