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Finding the Fourth Proportional to 789.70, 1,089.30 and 491.11

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Solution

The fourth proportional to 789.70, 1,089.30 and 491.11 is: 677.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.70 : 1,089.30 = 491.11 : x
  2. Step 2: Convert to fraction form
    789.70/1,089.30 = 491.11/x
  3. Step 3: Cross multiply
    789.70x = 1,089.30 × 491.11
  4. Step 4: Simplify right side
    789.70x = 534,968.61
  5. Step 5: Solve for x
    x = 534,968.61/789.70
  6. Step 6: Final answer
    x = 677.43

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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.