Think of a number, that when multiplied with itself, will get you 90.
We could try something like 7. So 7*7 = 49, but it's too small.
How about 10? Well we get 10*10 = 100 which is too big. The answer is between 7 and 10.
Let's try 8. So we get 8*8 = 64 which is too small.
This process is repeated until you determine that the answer is somewhere between 9 and 10
9*9 = 81
10*10 = 100
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From here, we can try 9.5 since it's right between 9 and 10
9.5*9.5 = 90.25
close but not quite there. It's a bit too large. So the actual value is somewhat smaller than 9.5
Let's try 9.4
9.4*9.4 = 88.36
That seems even worse off compared to 90.25, so 9.5 is the better answer.
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As a shortcut, you can use the square root on your calculator
[tex]\sqrt{90} \approx 9.4868 \approx 9.5[/tex]
