Math Problem Statement

Compare -√7 and -3.12345.... Justify your reasoning.

Solution

To compare 7-\sqrt{7} and 3.12345-3.12345\ldots, we will calculate the approximate value of 7\sqrt{7} and then compare the two numbers.

  1. 72.64575\sqrt{7} \approx 2.64575, so: 72.64575-\sqrt{7} \approx -2.64575

  2. The second number is 3.12345-3.12345\ldots, which is already given.

Now let's compare:

  • 72.64575-\sqrt{7} \approx -2.64575
  • 3.12345-3.12345\ldots

Since 3.12345-3.12345\ldots is smaller (more negative) than 2.64575-2.64575, we can conclude that: 7>3.12345-\sqrt{7} > -3.12345\ldots

Justification:

The comparison is based on their decimal approximations. Since 7-\sqrt{7} is closer to 0 than 3.12345-3.12345\ldots, it is the larger of the two numbers.


Would you like further details on how the square root was calculated or any other questions?

5 Related Questions:

  1. How do you approximate square roots without a calculator?
  2. What is the exact value of 7\sqrt{7}?
  3. Why is 2.64575-2.64575 larger than 3.12345-3.12345?
  4. How can you compare square roots of non-perfect squares?
  5. What other methods can be used to compare irrational and decimal numbers?

Tip:

When comparing negative numbers, the one closer to zero is always the larger number.

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Math Problem Analysis

Mathematical Concepts

Square Roots
Negative Numbers
Irrational Numbers
Decimal Numbers

Formulas

√7 ≈ 2.64575

Theorems

Comparison of real numbers
Properties of square roots
Order of negative numbers

Suitable Grade Level

Grades 9-12