In the first section of Algebra 1 we learned that
We said that 9 was the square of 3. The square of -3 is 9 as
3 and -3 are said to be the square roots of 9.
All positive real numbers has two square roots, one positive
square root and one negative square root. The positive square root
is sometimes referred to as the principal square root. The reason
that we have two square roots is exemplified above. The product of
two numbers is positive if both numbers have the same sign as is
the case with squares and square roots
A square root is written with a radical symbol √ and the number
or expression inside the radical symbol, below denoted a, is called
To indicate that we want both the positive and the negative
square root of a radicand we put the symbol ± (read as plus minus)
in front of the root.
Zero has one square root which is 0.
Negative numbers don't have real square roots since a square is
either positive or 0.
If the square root of an integer is another integer then the
square is called a perfect square. For example 25 is a perfect
If the radicand is not a perfect square i.e. the square root is
not a whole number than you have to approximate the square root
The square roots of numbers that are not a perfect square are
members of the irrational numbers. This means that they can't be
written as the quotient of two integers. The decimal form of an
irrational number will neither terminate nor repeat. The irrational
numbers together with the rational numbers constitutes the real
Videolesson: Approximate the square root of