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Finding the Fourth Proportional to 80.86, 121.15 and 72.46

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Solution

The fourth proportional to 80.86, 121.15 and 72.46 is: 108.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.86 : 121.15 = 72.46 : x
  2. Step 2: Convert to fraction form
    80.86/121.15 = 72.46/x
  3. Step 3: Cross multiply
    80.86x = 121.15 × 72.46
  4. Step 4: Simplify right side
    80.86x = 8,778.53
  5. Step 5: Solve for x
    x = 8,778.53/80.86
  6. Step 6: Final answer
    x = 108.56

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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.