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Finding the Fourth Proportional to 80.35, 121.11 and 74.78

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Solution

The fourth proportional to 80.35, 121.11 and 74.78 is: 112.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.35 : 121.11 = 74.78 : x
  2. Step 2: Convert to fraction form
    80.35/121.11 = 74.78/x
  3. Step 3: Cross multiply
    80.35x = 121.11 × 74.78
  4. Step 4: Simplify right side
    80.35x = 9,056.61
  5. Step 5: Solve for x
    x = 9,056.61/80.35
  6. Step 6: Final answer
    x = 112.71

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.