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Finding the Fourth Proportional to 81.68, 122.36 and 57.68

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Solution

The fourth proportional to 81.68, 122.36 and 57.68 is: 86.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.68 : 122.36 = 57.68 : x
  2. Step 2: Convert to fraction form
    81.68/122.36 = 57.68/x
  3. Step 3: Cross multiply
    81.68x = 122.36 × 57.68
  4. Step 4: Simplify right side
    81.68x = 7,057.72
  5. Step 5: Solve for x
    x = 7,057.72/81.68
  6. Step 6: Final answer
    x = 86.41

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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.