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Finding the Fourth Proportional to 139.07, 191.91 and 76.91

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Solution

The fourth proportional to 139.07, 191.91 and 76.91 is: 106.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.07 : 191.91 = 76.91 : x
  2. Step 2: Convert to fraction form
    139.07/191.91 = 76.91/x
  3. Step 3: Cross multiply
    139.07x = 191.91 × 76.91
  4. Step 4: Simplify right side
    139.07x = 14,759.13
  5. Step 5: Solve for x
    x = 14,759.13/139.07
  6. Step 6: Final answer
    x = 106.13

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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.