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Finding the Fourth Proportional to 728.48, 1,005.31 and 396.91

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Solution

The fourth proportional to 728.48, 1,005.31 and 396.91 is: 547.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.48 : 1,005.31 = 396.91 : x
  2. Step 2: Convert to fraction form
    728.48/1,005.31 = 396.91/x
  3. Step 3: Cross multiply
    728.48x = 1,005.31 × 396.91
  4. Step 4: Simplify right side
    728.48x = 399,020.76
  5. Step 5: Solve for x
    x = 399,020.76/728.48
  6. Step 6: Final answer
    x = 547.74

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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.