I found an algorithm to determinate the Square roots without a calculator: http://www.homeschoolmath.net/teaching/square-root-algorithm.php
You're absolutely right.
The answer is 1296
You have to divide both numerator (the upper number) and denominator (the downer number) by their Highest Common Factor (HCF). If their HCF is 1, you can't reduce : they are called COPRIME numbers.
The area of a circle of radius r is $$\pi r^2$$
π is approximately 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848111745028410270193852110555964462294895493038196
3.14159265358979323846264338327950288419716939937510
582097494459230781640628620899862803482534211706798
214808651328230664709384460955058223172535940812848
111745028410270193852110555964462294895493038196
The area of a circle of radius r is: $$\pi r^2$$
The volume of a sphere of radius r is: $$\frac{4\pi r^3}{3}$$
So the area of the ball is 5026.5482457436691815 cm²
And the volume is 268082.5731063290230155 cm³
$$\sqrt{x}-3\sqrt{x}=8\\ x=4$$
-5.5 is the smallest
+870 
