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Finding the Fourth Proportional to 138.60, 206.31 and 138

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Solution

The fourth proportional to 138.60, 206.31 and 138 is: 205.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.60 : 206.31 = 138 : x
  2. Step 2: Convert to fraction form
    138.60/206.31 = 138/x
  3. Step 3: Cross multiply
    138.60x = 206.31 × 138
  4. Step 4: Simplify right side
    138.60x = 28,470.78
  5. Step 5: Solve for x
    x = 28,470.78/138.60
  6. Step 6: Final answer
    x = 205.42

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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.