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Finding the Fourth Proportional to 645.85, 969.17 and 255.78

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Solution

The fourth proportional to 645.85, 969.17 and 255.78 is: 383.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.85 : 969.17 = 255.78 : x
  2. Step 2: Convert to fraction form
    645.85/969.17 = 255.78/x
  3. Step 3: Cross multiply
    645.85x = 969.17 × 255.78
  4. Step 4: Simplify right side
    645.85x = 247,893.02
  5. Step 5: Solve for x
    x = 247,893.02/645.85
  6. Step 6: Final answer
    x = 383.83

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.