Big Ideas Math: Modeling Real Life, Grade 8
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Exercise 13 Page 418

Think of a number that is 64343 when it is multiplied by itself three times.

4/7

Practice makes perfect
The cube root of a number a is another number b if b multiplied by itself three times is a. This means that if b is the cube root of a, then b raised to the third power results in a. Let's see some examples of this. sqrt(a)= b because b^3= a [0.8em] c|c sqrt(- 8)= - 2 & sqrt(27)= 3 because( - 2)^3= - 8 & because 3^3= 27 We will now find the cube root of 64343. We need to think of a number that is 64343 when it is multiplied by itself three times. ?^3= 64/343 We see that 47 raised to the third power is 64343, so the number we are looking for is 47.
(4/7)(4/7)(4/7)
4*4*4/7*7*7
4^3/7^3
64/343
This means that the cube root of 64343 is 47. sqrt(64/343) = 4/7