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Finding the Fourth Proportional to 789.90, 1,089.47 and 580

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Solution

The fourth proportional to 789.90, 1,089.47 and 580 is: 799.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.90 : 1,089.47 = 580 : x
  2. Step 2: Convert to fraction form
    789.90/1,089.47 = 580/x
  3. Step 3: Cross multiply
    789.90x = 1,089.47 × 580
  4. Step 4: Simplify right side
    789.90x = 631,892.60
  5. Step 5: Solve for x
    x = 631,892.60/789.90
  6. Step 6: Final answer
    x = 799.97

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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.