OBJECTIVE
•Rationalize the denominator
of a radical expression.
Rationalizing the denominator
•means to find a radical expression
which when we multiplied to both
numerator and denominator will
make the denominator a perfect
square which then simplifies to a
rational expression.
•A radical is not considered simplified if
there is a radical sign in the
denominator.
•To remove the radical sign is to
rationalize.
•The process of eliminating the radicals
in the denominator is called
rationalization.
6
3
2
6
There is an agreement
3
1
in mathematics
that we don’t leave a radical
in the denominator
of a fraction.
So how do we change the
denominator of a fraction?
3
1
(Without changing the value of
the fraction, of course.)
By what number
to a rational number?
to change it
3
1
3
can we multiply
The answer is . . .
3
1
3
. . . by itself!
 3   23 3
In our fraction, to get the radical
out of the denominator,
we can multiply numerator and
denominator by .3
3
1

3
1

33
31
3
3
In our fraction, to get the radical
out of the denominator,
we can multiply numerator and
denominator by .3

3
1
3
3
Because we are changing
the denominator
we call this process
rationalizing.
to a rational number,

2
4

22
24
Rationalize the denominator:

2
24
22
2

12
64

12
8

1212
128
Rationalize the denominator:
3
6
3

12
96
Rationalize the following:
•

Rationalizing the Denominator of a Radical Expression