First step of finding the square root is finding the perfect squares closest to the number 87. I found for a low square root 81.
9×9=81
By mutiplying 9 by itself you get 81 over 9. I found the higher perfect square of 100 by timesing 10 by itself.
10×10=100
After that, I found that 87 is closer to 81. Its not in between the numbers because if it was it would be 91.5 making the number an obivous 9.5. But in that case the number 87 is closer to 81 than it is to 100. So knowing that I guess the number 9.4 to start out with. So to do this you have to times 9.4 times itself.
9.4×9.4=88.36
88.36 is very close to 87 but I belive I can get closer. So next I try 9.3.
9.3×9.3=86.49
We are getting very, very close but I am going to take it to the tenths decimal. So I know the number is alittle higher than 9.3 so I am going to true 9.34.
9.34×9.34=87.23
I belive that is the closest I am going to get to the number 87.