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Finding the Fourth Proportional to 728.21, 1,004.90 and 396.61

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Solution

The fourth proportional to 728.21, 1,004.90 and 396.61 is: 547.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.21 : 1,004.90 = 396.61 : x
  2. Step 2: Convert to fraction form
    728.21/1,004.90 = 396.61/x
  3. Step 3: Cross multiply
    728.21x = 1,004.90 × 396.61
  4. Step 4: Simplify right side
    728.21x = 398,555.66
  5. Step 5: Solve for x
    x = 398,555.66/728.21
  6. Step 6: Final answer
    x = 547.31

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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.