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Finding the Fourth Proportional to 138.35, 207.23 and 128.86

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Solution

The fourth proportional to 138.35, 207.23 and 128.86 is: 193.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.35 : 207.23 = 128.86 : x
  2. Step 2: Convert to fraction form
    138.35/207.23 = 128.86/x
  3. Step 3: Cross multiply
    138.35x = 207.23 × 128.86
  4. Step 4: Simplify right side
    138.35x = 26,702.62
  5. Step 5: Solve for x
    x = 26,702.62/138.35
  6. Step 6: Final answer
    x = 193.01

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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.