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Finding the Fourth Proportional to 728.56, 1,005.40 and 397

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Solution

The fourth proportional to 728.56, 1,005.40 and 397 is: 547.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.56 : 1,005.40 = 397 : x
  2. Step 2: Convert to fraction form
    728.56/1,005.40 = 397/x
  3. Step 3: Cross multiply
    728.56x = 1,005.40 × 397
  4. Step 4: Simplify right side
    728.56x = 399,143.80
  5. Step 5: Solve for x
    x = 399,143.80/728.56
  6. Step 6: Final answer
    x = 547.85

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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.