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Finding the Fourth Proportional to 491.20, 726.77 and 489.85

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Solution

The fourth proportional to 491.20, 726.77 and 489.85 is: 724.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.20 : 726.77 = 489.85 : x
  2. Step 2: Convert to fraction form
    491.20/726.77 = 489.85/x
  3. Step 3: Cross multiply
    491.20x = 726.77 × 489.85
  4. Step 4: Simplify right side
    491.20x = 356,007.69
  5. Step 5: Solve for x
    x = 356,007.69/491.20
  6. Step 6: Final answer
    x = 724.78

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Why These Related Problems?

These problems maintain the same ratio (1.48) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.