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Finding the Fourth Proportional to 204.78, 307.12 and 139.73

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Solution

The fourth proportional to 204.78, 307.12 and 139.73 is: 209.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    204.78 : 307.12 = 139.73 : x
  2. Step 2: Convert to fraction form
    204.78/307.12 = 139.73/x
  3. Step 3: Cross multiply
    204.78x = 307.12 × 139.73
  4. Step 4: Simplify right side
    204.78x = 42,913.88
  5. Step 5: Solve for x
    x = 42,913.88/204.78
  6. Step 6: Final answer
    x = 209.56

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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.