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Finding the Fourth Proportional to 138.81, 206.69 and 136.90

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Solution

The fourth proportional to 138.81, 206.69 and 136.90 is: 203.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.81 : 206.69 = 136.90 : x
  2. Step 2: Convert to fraction form
    138.81/206.69 = 136.90/x
  3. Step 3: Cross multiply
    138.81x = 206.69 × 136.90
  4. Step 4: Simplify right side
    138.81x = 28,295.86
  5. Step 5: Solve for x
    x = 28,295.86/138.81
  6. Step 6: Final answer
    x = 203.85

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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.