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Finding the Fourth Proportional to 382.78, 574.31 and 139.38

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Solution

The fourth proportional to 382.78, 574.31 and 139.38 is: 209.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    382.78 : 574.31 = 139.38 : x
  2. Step 2: Convert to fraction form
    382.78/574.31 = 139.38/x
  3. Step 3: Cross multiply
    382.78x = 574.31 × 139.38
  4. Step 4: Simplify right side
    382.78x = 80,047.33
  5. Step 5: Solve for x
    x = 80,047.33/382.78
  6. Step 6: Final answer
    x = 209.12

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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.