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Finding the Fourth Proportional to 439.88, 660.68 and 420.74

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Solution

The fourth proportional to 439.88, 660.68 and 420.74 is: 631.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.88 : 660.68 = 420.74 : x
  2. Step 2: Convert to fraction form
    439.88/660.68 = 420.74/x
  3. Step 3: Cross multiply
    439.88x = 660.68 × 420.74
  4. Step 4: Simplify right side
    439.88x = 277,974.50
  5. Step 5: Solve for x
    x = 277,974.50/439.88
  6. Step 6: Final answer
    x = 631.93

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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.