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Finding the Fourth Proportional to 789.76, 1,089.42 and 680.68

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Solution

The fourth proportional to 789.76, 1,089.42 and 680.68 is: 938.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.76 : 1,089.42 = 680.68 : x
  2. Step 2: Convert to fraction form
    789.76/1,089.42 = 680.68/x
  3. Step 3: Cross multiply
    789.76x = 1,089.42 × 680.68
  4. Step 4: Simplify right side
    789.76x = 741,546.41
  5. Step 5: Solve for x
    x = 741,546.41/789.76
  6. Step 6: Final answer
    x = 938.95

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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.