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Finding the Fourth Proportional to 139.15, 192.11 and 86.76

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Solution

The fourth proportional to 139.15, 192.11 and 86.76 is: 119.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.15 : 192.11 = 86.76 : x
  2. Step 2: Convert to fraction form
    139.15/192.11 = 86.76/x
  3. Step 3: Cross multiply
    139.15x = 192.11 × 86.76
  4. Step 4: Simplify right side
    139.15x = 16,667.46
  5. Step 5: Solve for x
    x = 16,667.46/139.15
  6. Step 6: Final answer
    x = 119.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.