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Finding the Fourth Proportional to 142.25, 213.21 and 81.41

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Solution

The fourth proportional to 142.25, 213.21 and 81.41 is: 122.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.25 : 213.21 = 81.41 : x
  2. Step 2: Convert to fraction form
    142.25/213.21 = 81.41/x
  3. Step 3: Cross multiply
    142.25x = 213.21 × 81.41
  4. Step 4: Simplify right side
    142.25x = 17,357.43
  5. Step 5: Solve for x
    x = 17,357.43/142.25
  6. Step 6: Final answer
    x = 122.02

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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.