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Finding the Fourth Proportional to 142.14, 213.03 and 81.12

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Solution

The fourth proportional to 142.14, 213.03 and 81.12 is: 121.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.14 : 213.03 = 81.12 : x
  2. Step 2: Convert to fraction form
    142.14/213.03 = 81.12/x
  3. Step 3: Cross multiply
    142.14x = 213.03 × 81.12
  4. Step 4: Simplify right side
    142.14x = 17,280.99
  5. Step 5: Solve for x
    x = 17,280.99/142.14
  6. Step 6: Final answer
    x = 121.58

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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.