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Finding the Fourth Proportional to 139.87, 208.17 and 138.76

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Solution

The fourth proportional to 139.87, 208.17 and 138.76 is: 206.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.87 : 208.17 = 138.76 : x
  2. Step 2: Convert to fraction form
    139.87/208.17 = 138.76/x
  3. Step 3: Cross multiply
    139.87x = 208.17 × 138.76
  4. Step 4: Simplify right side
    139.87x = 28,885.15
  5. Step 5: Solve for x
    x = 28,885.15/139.87
  6. Step 6: Final answer
    x = 206.52

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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.