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Finding the Fourth Proportional to 789.12, 1,089.36 and 557.28

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Solution

The fourth proportional to 789.12, 1,089.36 and 557.28 is: 769.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.12 : 1,089.36 = 557.28 : x
  2. Step 2: Convert to fraction form
    789.12/1,089.36 = 557.28/x
  3. Step 3: Cross multiply
    789.12x = 1,089.36 × 557.28
  4. Step 4: Simplify right side
    789.12x = 607,078.54
  5. Step 5: Solve for x
    x = 607,078.54/789.12
  6. Step 6: Final answer
    x = 769.31

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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.