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Finding the Fourth Proportional to 142.66, 213.64 and 81.61

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Solution

The fourth proportional to 142.66, 213.64 and 81.61 is: 122.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.66 : 213.64 = 81.61 : x
  2. Step 2: Convert to fraction form
    142.66/213.64 = 81.61/x
  3. Step 3: Cross multiply
    142.66x = 213.64 × 81.61
  4. Step 4: Simplify right side
    142.66x = 17,435.16
  5. Step 5: Solve for x
    x = 17,435.16/142.66
  6. Step 6: Final answer
    x = 122.21

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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.