Unit 8, Lesson 12
Edge Lengths, Volumes, and Cube Roots
Accelerated 7
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The numbers
For a square, its side length is the square root of its area. For example, this square has an area of 16 square units and a side length of 4 units.
Both of these equations are true:
For a cube, the edge length is the cube root of its volume. For example, this cube has a volume of 64 cubic units and an edge length of 4 units:
Both of these equations are true:
Like square roots, most cube roots of whole numbers are irrational. The only time the cube root of a number is a rational number is when the number we are taking the cube root of is a perfect cube. For example, 8 is a perfect cube, and
We can approximate the values of the cube root of a number by observing the integers around it and remembering the relationship between cubes and cube roots. For example,
The cube root of a number
The cube root of 64 is written as
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