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Finding the Fourth Proportional to 728.91, 1,005.86 and 397.31

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Solution

The fourth proportional to 728.91, 1,005.86 and 397.31 is: 548.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.91 : 1,005.86 = 397.31 : x
  2. Step 2: Convert to fraction form
    728.91/1,005.86 = 397.31/x
  3. Step 3: Cross multiply
    728.91x = 1,005.86 × 397.31
  4. Step 4: Simplify right side
    728.91x = 399,631.22
  5. Step 5: Solve for x
    x = 399,631.22/728.91
  6. Step 6: Final answer
    x = 548.26

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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.