Math Problem Statement

Why 3² and not 3³ as answer?

Solution

To explain why 323^2 is the correct answer, let's revisit the goal: we want to make 27783 a perfect cube by multiplying it by the smallest possible number.

Prime Factorization of 27783

As we previously determined: 27783=34×7327783 = 3^4 \times 7^3

Requirements for a Perfect Cube

For a number to be a perfect cube, all the exponents in its prime factorization must be multiples of 3. Currently, the exponents are:

  • 343^4: Exponent is 4
  • 737^3: Exponent is 3

Adjusting the Exponents

  • For 343^4:
    • The exponent 4 needs to be increased to the nearest multiple of 3, which is 6. Therefore, we need 364=323^{6-4} = 3^2.
  • For 737^3:
    • The exponent 3 is already a multiple of 3, so no adjustment is needed.

Multiplication Factor

To make the exponent of 3 a multiple of 3, we need: 323^2

So, the smallest number by which 27783 should be multiplied to make it a perfect cube is 32=93^2 = 9.

Therefore, the smallest number is 9\boxed{9}.

Would you like more details or have any questions?

Here are 8 related questions:

  1. How do we determine the prime factorization of a number?
  2. Why must the exponents in the prime factorization be multiples of 3 for a perfect cube?
  3. What is the difference between perfect squares, perfect cubes, and other perfect powers?
  4. How can you verify that a number is a perfect cube?
  5. What are some examples of perfect cubes?
  6. How does the process change for finding the smallest number to multiply to get a perfect fourth power?
  7. Can you explain the significance of the smallest multiplier in other mathematical contexts?
  8. How can prime factorization be used in other areas of mathematics?

Tip: Always ensure that all exponents in the prime factorization of a perfect power are adjusted to the required multiple, not just the smallest necessary increment.

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Math Problem Analysis

Mathematical Concepts

Exponents
Prime Factorization
Perfect Powers

Formulas

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Theorems

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Suitable Grade Level

Grades 6-8