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Finding the Fourth Proportional to 439.14, 657.90 and 390.54

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Solution

The fourth proportional to 439.14, 657.90 and 390.54 is: 585.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.14 : 657.90 = 390.54 : x
  2. Step 2: Convert to fraction form
    439.14/657.90 = 390.54/x
  3. Step 3: Cross multiply
    439.14x = 657.90 × 390.54
  4. Step 4: Simplify right side
    439.14x = 256,936.27
  5. Step 5: Solve for x
    x = 256,936.27/439.14
  6. Step 6: Final answer
    x = 585.09

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.