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Finding the Fourth Proportional to 789.20, 1,089.28 and 490.56

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Solution

The fourth proportional to 789.20, 1,089.28 and 490.56 is: 677.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.20 : 1,089.28 = 490.56 : x
  2. Step 2: Convert to fraction form
    789.20/1,089.28 = 490.56/x
  3. Step 3: Cross multiply
    789.20x = 1,089.28 × 490.56
  4. Step 4: Simplify right side
    789.20x = 534,357.20
  5. Step 5: Solve for x
    x = 534,357.20/789.20
  6. Step 6: Final answer
    x = 677.09

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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.