1. √99 and √21 are irrational. √225 = 15, so is rational. Set c has all rational numbers.
2. √3 and π are the only irrational numbers in the group.
3. In decimal form, these numbers are approximately
... 2.45, 2.50, -1.00, 3.50, 3.33
In order from least to greatest, they are
... -√1, √6, 2 1/2, 3 1/3, 7/2 . . . . . . (How do you cut ribbon to length -1?)
4. You can solve these by taking the corresponding root. Remember that the square of a negative number is positive. It is helpful to know the squares and cubes of small integers. Your calculator can also help with this, though you have to know that (-13)² = 169 as well as 13² = 169.
a) x = ±√169 = ±13
b) x = ∛-125 = -5
