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Finding the Third Proportional to 257.25 and 399.38

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Solution

The third proportional to 257.25 and 399.38 is: 620.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.25 : 399.38 = 399.38 : x
  2. Step 2: Convert to fraction form
    257.25/399.38 = 399.38/x
  3. Step 3: Cross multiply
    257.25x = 399.38 × 399.38
  4. Step 4: Simplify right side
    257.25x = 159,500.39
  5. Step 5: Solve for x
    x = 159,500.39/257.25
  6. Step 6: Final answer
    x = 620.02

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Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.