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Finding the Fourth Proportional to 138.10, 206.88 and 83.86

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Solution

The fourth proportional to 138.10, 206.88 and 83.86 is: 125.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.10 : 206.88 = 83.86 : x
  2. Step 2: Convert to fraction form
    138.10/206.88 = 83.86/x
  3. Step 3: Cross multiply
    138.10x = 206.88 × 83.86
  4. Step 4: Simplify right side
    138.10x = 17,348.96
  5. Step 5: Solve for x
    x = 17,348.96/138.10
  6. Step 6: Final answer
    x = 125.63

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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.