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Finding the Fourth Proportional to 137.39, 206.03 and 128.78

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Solution

The fourth proportional to 137.39, 206.03 and 128.78 is: 193.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.39 : 206.03 = 128.78 : x
  2. Step 2: Convert to fraction form
    137.39/206.03 = 128.78/x
  3. Step 3: Cross multiply
    137.39x = 206.03 × 128.78
  4. Step 4: Simplify right side
    137.39x = 26,531.90
  5. Step 5: Solve for x
    x = 26,531.90/137.39
  6. Step 6: Final answer
    x = 193.12

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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.