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Finding the Fourth Proportional to 101.43, 140.13 and 81.72

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Solution

The fourth proportional to 101.43, 140.13 and 81.72 is: 112.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.43 : 140.13 = 81.72 : x
  2. Step 2: Convert to fraction form
    101.43/140.13 = 81.72/x
  3. Step 3: Cross multiply
    101.43x = 140.13 × 81.72
  4. Step 4: Simplify right side
    101.43x = 11,451.42
  5. Step 5: Solve for x
    x = 11,451.42/101.43
  6. Step 6: Final answer
    x = 112.90

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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.