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Finding the Fourth Proportional to 85.72, 127.97 and 82.12

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Solution

The fourth proportional to 85.72, 127.97 and 82.12 is: 122.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.72 : 127.97 = 82.12 : x
  2. Step 2: Convert to fraction form
    85.72/127.97 = 82.12/x
  3. Step 3: Cross multiply
    85.72x = 127.97 × 82.12
  4. Step 4: Simplify right side
    85.72x = 10,508.90
  5. Step 5: Solve for x
    x = 10,508.90/85.72
  6. Step 6: Final answer
    x = 122.60

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.