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Finding the Fourth Proportional to 138.76, 208.14 and 108.40

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Solution

The fourth proportional to 138.76, 208.14 and 108.40 is: 162.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.76 : 208.14 = 108.40 : x
  2. Step 2: Convert to fraction form
    138.76/208.14 = 108.40/x
  3. Step 3: Cross multiply
    138.76x = 208.14 × 108.40
  4. Step 4: Simplify right side
    138.76x = 22,562.38
  5. Step 5: Solve for x
    x = 22,562.38/138.76
  6. Step 6: Final answer
    x = 162.60

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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.