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Finding the Fourth Proportional to 142.23, 213.13 and 81.38

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Solution

The fourth proportional to 142.23, 213.13 and 81.38 is: 121.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.23 : 213.13 = 81.38 : x
  2. Step 2: Convert to fraction form
    142.23/213.13 = 81.38/x
  3. Step 3: Cross multiply
    142.23x = 213.13 × 81.38
  4. Step 4: Simplify right side
    142.23x = 17,344.52
  5. Step 5: Solve for x
    x = 17,344.52/142.23
  6. Step 6: Final answer
    x = 121.95

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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.