Equalizing radicals by squaring: Solve for ? if √(25/15625) = √(?/30625).

Difficulty: Easy

Correct Answer: 49

Explanation:


Introduction / Context:
When two square roots are equal, their radicands (nonnegative) must be equal. We simplify one side and equate the interior fractions to find the missing numerator.


Given Data / Assumptions:

  • √(25/15625) = √(?/30625).
  • All quantities are nonnegative.

Concept / Approach:
First simplify 25/15625. Then set the simplified fraction equal to ?/30625 and solve for the unknown numerator.


Step-by-Step Solution:

25/15625 = 1/625 (divide numerator and denominator by 25).So √(25/15625) = √(1/625) = 1/25.Given equality of square roots ⇒ ?/30625 = 1/625.Cross-multiply: ? = 30625 / 625 = 49.

Verification / Alternative check:
Compute √(?/30625) with ? = 49: 49/30625 = 1/625; √(1/625) = 1/25, matching the left side.


Why Other Options Are Wrong:

  • 2, 35, 1225, 625 do not produce the same radicand 1/625 on the right side.

Common Pitfalls:
Equating the square roots without equating the radicands, or forgetting to simplify 25/15625 first.


Final Answer:
49

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