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Finding the Fourth Proportional to 81.61, 122.45 and 43.11

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Solution

The fourth proportional to 81.61, 122.45 and 43.11 is: 64.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.61 : 122.45 = 43.11 : x
  2. Step 2: Convert to fraction form
    81.61/122.45 = 43.11/x
  3. Step 3: Cross multiply
    81.61x = 122.45 × 43.11
  4. Step 4: Simplify right side
    81.61x = 5,278.60
  5. Step 5: Solve for x
    x = 5,278.60/81.61
  6. Step 6: Final answer
    x = 64.68

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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.