The square root of 800 is 28.2842712475, which, when rounded off to four significant figures, equals 28.28. It is a decimal number, which shows that 800 is not a perfect square.
If a and b are two numbers such that a^2 = b, then a is known as the square root of b. If b is a positive real number, then it has two square roots, out of which one is positive and the other is negative. In order to find the square root of a negative number, one should know about complex numbers. Square roots of positive whole numbers that are not perfect squares are irrational or fractional numbers.