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Finding the Fourth Proportional to 728.78, 1,005.72 and 418.28

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Solution

The fourth proportional to 728.78, 1,005.72 and 418.28 is: 577.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.78 : 1,005.72 = 418.28 : x
  2. Step 2: Convert to fraction form
    728.78/1,005.72 = 418.28/x
  3. Step 3: Cross multiply
    728.78x = 1,005.72 × 418.28
  4. Step 4: Simplify right side
    728.78x = 420,672.56
  5. Step 5: Solve for x
    x = 420,672.56/728.78
  6. Step 6: Final answer
    x = 577.23

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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.