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Finding the Fourth Proportional to 678.20, 930.39 and 636.29

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Solution

The fourth proportional to 678.20, 930.39 and 636.29 is: 872.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.20 : 930.39 = 636.29 : x
  2. Step 2: Convert to fraction form
    678.20/930.39 = 636.29/x
  3. Step 3: Cross multiply
    678.20x = 930.39 × 636.29
  4. Step 4: Simplify right side
    678.20x = 591,997.85
  5. Step 5: Solve for x
    x = 591,997.85/678.20
  6. Step 6: Final answer
    x = 872.90

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.