Question

Is -19.78 a irrational or rational # ????

Answer 1

Rational because it can be written as a fraction while a number like 3.8873542..... cannot be.

Answer 2

Okay thank you! what about something like this though...?
\[\sqrt{-3}/5 + 10.8\]

Answer 3

Irrational or rational?

Answer 4

That is irrational because you would get imaginary numbers. Because you have a negative under the radical.

Answer 5

So if its negative its always irrational???

Answer 6

-0.8662866239 would be irrational?

Answer 7

irrational numbers have an unending, non-repeating decimal digits

For example, if you find the square root of 3 your calculator gives
1.732050808

but if your calculator printed more digits you would see
\[ \sqrt{3} \approx 1.732050807568877293527446341505872366942805253810380628055806979451933016908800037081146186757248576
\]
and it really goes on forever

Answer 8

Okay, that helps a lot thank you!!!

Answer 9

square root and cube roots are almost always irrational except for special numbers (perfect squares or perfect cubes)

for example sqr(24) is irrational
sqr(25) = 5 (because 25 is a perfect square= 5*5)

Answer 10

okay thank you!

Answer 11

Im getting it a lot more now