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Finding the Fourth Proportional to 139.09, 191.90 and 80.86

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Solution

The fourth proportional to 139.09, 191.90 and 80.86 is: 111.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.09 : 191.90 = 80.86 : x
  2. Step 2: Convert to fraction form
    139.09/191.90 = 80.86/x
  3. Step 3: Cross multiply
    139.09x = 191.90 × 80.86
  4. Step 4: Simplify right side
    139.09x = 15,515.67
  5. Step 5: Solve for x
    x = 15,515.67/139.09
  6. Step 6: Final answer
    x = 111.56

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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.