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Finding the Fourth Proportional to 143.28, 197.71 and 81.11

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Solution

The fourth proportional to 143.28, 197.71 and 81.11 is: 111.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.28 : 197.71 = 81.11 : x
  2. Step 2: Convert to fraction form
    143.28/197.71 = 81.11/x
  3. Step 3: Cross multiply
    143.28x = 197.71 × 81.11
  4. Step 4: Simplify right side
    143.28x = 16,036.55
  5. Step 5: Solve for x
    x = 16,036.55/143.28
  6. Step 6: Final answer
    x = 111.92

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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.