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Finding the Fourth Proportional to 139.88, 209.90 and 75.76

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Solution

The fourth proportional to 139.88, 209.90 and 75.76 is: 113.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.88 : 209.90 = 75.76 : x
  2. Step 2: Convert to fraction form
    139.88/209.90 = 75.76/x
  3. Step 3: Cross multiply
    139.88x = 209.90 × 75.76
  4. Step 4: Simplify right side
    139.88x = 15,902.02
  5. Step 5: Solve for x
    x = 15,902.02/139.88
  6. Step 6: Final answer
    x = 113.68

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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.