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Finding the Fourth Proportional to 143.28, 197.70 and 81.09

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Solution

The fourth proportional to 143.28, 197.70 and 81.09 is: 111.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.28 : 197.70 = 81.09 : x
  2. Step 2: Convert to fraction form
    143.28/197.70 = 81.09/x
  3. Step 3: Cross multiply
    143.28x = 197.70 × 81.09
  4. Step 4: Simplify right side
    143.28x = 16,031.49
  5. Step 5: Solve for x
    x = 16,031.49/143.28
  6. Step 6: Final answer
    x = 111.89

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.