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Finding the Fourth Proportional to 143.38, 213.89 and 139.78

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Solution

The fourth proportional to 143.38, 213.89 and 139.78 is: 208.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.38 : 213.89 = 139.78 : x
  2. Step 2: Convert to fraction form
    143.38/213.89 = 139.78/x
  3. Step 3: Cross multiply
    143.38x = 213.89 × 139.78
  4. Step 4: Simplify right side
    143.38x = 29,897.54
  5. Step 5: Solve for x
    x = 29,897.54/143.38
  6. Step 6: Final answer
    x = 208.52

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.