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Finding the Fourth Proportional to 728.47, 1,005.30 and 396.90

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Solution

The fourth proportional to 728.47, 1,005.30 and 396.90 is: 547.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.47 : 1,005.30 = 396.90 : x
  2. Step 2: Convert to fraction form
    728.47/1,005.30 = 396.90/x
  3. Step 3: Cross multiply
    728.47x = 1,005.30 × 396.90
  4. Step 4: Simplify right side
    728.47x = 399,003.57
  5. Step 5: Solve for x
    x = 399,003.57/728.47
  6. Step 6: Final answer
    x = 547.73

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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.