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Finding the Fourth Proportional to 86.86, 129.41 and 82.18

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Solution

The fourth proportional to 86.86, 129.41 and 82.18 is: 122.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.86 : 129.41 = 82.18 : x
  2. Step 2: Convert to fraction form
    86.86/129.41 = 82.18/x
  3. Step 3: Cross multiply
    86.86x = 129.41 × 82.18
  4. Step 4: Simplify right side
    86.86x = 10,634.91
  5. Step 5: Solve for x
    x = 10,634.91/86.86
  6. Step 6: Final answer
    x = 122.44

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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.