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Finding the Fourth Proportional to 81.54, 122.38 and 74.72

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Solution

The fourth proportional to 81.54, 122.38 and 74.72 is: 112.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.54 : 122.38 = 74.72 : x
  2. Step 2: Convert to fraction form
    81.54/122.38 = 74.72/x
  3. Step 3: Cross multiply
    81.54x = 122.38 × 74.72
  4. Step 4: Simplify right side
    81.54x = 9,144.35
  5. Step 5: Solve for x
    x = 9,144.35/81.54
  6. Step 6: Final answer
    x = 112.15

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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.