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Finding the Fourth Proportional to 728.50, 1,005.42 and 418

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Solution

The fourth proportional to 728.50, 1,005.42 and 418 is: 576.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.50 : 1,005.42 = 418 : x
  2. Step 2: Convert to fraction form
    728.50/1,005.42 = 418/x
  3. Step 3: Cross multiply
    728.50x = 1,005.42 × 418
  4. Step 4: Simplify right side
    728.50x = 420,265.56
  5. Step 5: Solve for x
    x = 420,265.56/728.50
  6. Step 6: Final answer
    x = 576.89

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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.