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Finding the Fourth Proportional to 439.20, 606.60 and 428.40

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Solution

The fourth proportional to 439.20, 606.60 and 428.40 is: 591.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.20 : 606.60 = 428.40 : x
  2. Step 2: Convert to fraction form
    439.20/606.60 = 428.40/x
  3. Step 3: Cross multiply
    439.20x = 606.60 × 428.40
  4. Step 4: Simplify right side
    439.20x = 259,867.44
  5. Step 5: Solve for x
    x = 259,867.44/439.20
  6. Step 6: Final answer
    x = 591.68

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.