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Finding the Fourth Proportional to 789.78, 1,089.09 and 684.78

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Solution

The fourth proportional to 789.78, 1,089.09 and 684.78 is: 944.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.78 : 1,089.09 = 684.78 : x
  2. Step 2: Convert to fraction form
    789.78/1,089.09 = 684.78/x
  3. Step 3: Cross multiply
    789.78x = 1,089.09 × 684.78
  4. Step 4: Simplify right side
    789.78x = 745,787.05
  5. Step 5: Solve for x
    x = 745,787.05/789.78
  6. Step 6: Final answer
    x = 944.30

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1.5x scale

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.