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Finding the Fourth Proportional to 439.85, 657.80 and 391.39

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Solution

The fourth proportional to 439.85, 657.80 and 391.39 is: 585.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.85 : 657.80 = 391.39 : x
  2. Step 2: Convert to fraction form
    439.85/657.80 = 391.39/x
  3. Step 3: Cross multiply
    439.85x = 657.80 × 391.39
  4. Step 4: Simplify right side
    439.85x = 257,451.10
  5. Step 5: Solve for x
    x = 257,451.10/439.85
  6. Step 6: Final answer
    x = 585.32

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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.