Cube Roots
Radical A radical is the term under a square root symbol. In the picture above, x would be the radical. Cube Root The expression for cube root is a small 3 above the radical/to the left. This number is called the index. To calculate the cube root of a number, we must find the number multiplied by itself, and then multiplied by itself again, is equaled to the original number. Problem #1 What is the cube root of 8? Step 1 We ask ourselves: What number multiplied by itself twice, equals 8? Step 2 Guess and check: Try 2 2 x 2 x 2 = 8 Therefore the cube root of 8 = 2 Answer: 2 Further Explanation Taking the cube root of a number is the inverse of cubing, therefore the answer is 2 because 2 3 = 8. If Problem #1’s explanation does not make sense, lets think about what we do when we cube a number. To cube a number, we multiply it 3 times. For example, when we cube the number 5: 5 x 5 x 5 = 125 A cube root goes in the...