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Finding the Fourth Proportional to 678.78, 1,017.42 and 331.56

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Solution

The fourth proportional to 678.78, 1,017.42 and 331.56 is: 496.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.78 : 1,017.42 = 331.56 : x
  2. Step 2: Convert to fraction form
    678.78/1,017.42 = 331.56/x
  3. Step 3: Cross multiply
    678.78x = 1,017.42 × 331.56
  4. Step 4: Simplify right side
    678.78x = 337,335.78
  5. Step 5: Solve for x
    x = 337,335.78/678.78
  6. Step 6: Final answer
    x = 496.97

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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.