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Finding the Fourth Proportional to 100.92, 139.07 and 77.61

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Solution

The fourth proportional to 100.92, 139.07 and 77.61 is: 106.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.92 : 139.07 = 77.61 : x
  2. Step 2: Convert to fraction form
    100.92/139.07 = 77.61/x
  3. Step 3: Cross multiply
    100.92x = 139.07 × 77.61
  4. Step 4: Simplify right side
    100.92x = 10,793.22
  5. Step 5: Solve for x
    x = 10,793.22/100.92
  6. Step 6: Final answer
    x = 106.95

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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.