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Finding the Fourth Proportional to 789.12, 1,177.74 and 685.80

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Solution

The fourth proportional to 789.12, 1,177.74 and 685.80 is: 1,023.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.12 : 1,177.74 = 685.80 : x
  2. Step 2: Convert to fraction form
    789.12/1,177.74 = 685.80/x
  3. Step 3: Cross multiply
    789.12x = 1,177.74 × 685.80
  4. Step 4: Simplify right side
    789.12x = 807,694.09
  5. Step 5: Solve for x
    x = 807,694.09/789.12
  6. Step 6: Final answer
    x = 1,023.54

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.