7.2 Finding Cube Roots
Essential Question: How is the cube root of a number
different than the square root of a number?
Vocabulary
Cube Root: A number that when multiplied by itself, and then
multiplied by itself again equals the given number.
Perfect Cube: A number that can be written as the cube of an integer.
𝟑
: A radical sign, used to represent a cube root
** Cubing a number and finding a cube root are inverse operations **
Example 1
Find each cube root
a.
d.
3
8
b.
3
− 216
e.
3
1
64
3
27
1000
c.
f.
3
3
−27
−343
Example 2
Evaluate each expression
3
a. 18 − 4 8
b.
(
3
125)3 +21
c.
3
2 −216 − 3
On Your Own
Evaluate each expression
3
a. 5 512 − 19
Example 3
Evaluate the expression for the given value of the variable.
a.
3
8𝑦 + 𝑦; 𝑦 = 64
b.
3
2𝑏 − 9𝑏; 𝑏 = −3
Example 3
Evaluate the expression for the given value of the variable.
c.
𝑥
4
+
3
𝑥
;x
3
= 192
Example 4
Solve for the missing variable
(3𝑥 + 4)3 = 2197
Real Life Example
The baseball display case is in the shape of a cube. Use the formula for
the volume of a cube to find the edge length s.
Make sure that last nights
homework is submitted first
before starting tonight's
You must do tonight’s
homework on Big Ideas.
You still need to turn in your
homework paper with the
work shown and answers to
class tomorrow!
Textbook pg.298 #2-20even, 24, 38
Leave this side open for
corrections.
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