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Finding the Fourth Proportional to 81.71, 122.68 and 80.46

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Solution

The fourth proportional to 81.71, 122.68 and 80.46 is: 120.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.71 : 122.68 = 80.46 : x
  2. Step 2: Convert to fraction form
    81.71/122.68 = 80.46/x
  3. Step 3: Cross multiply
    81.71x = 122.68 × 80.46
  4. Step 4: Simplify right side
    81.71x = 9,870.93
  5. Step 5: Solve for x
    x = 9,870.93/81.71
  6. Step 6: Final answer
    x = 120.81

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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.