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Finding the Fourth Proportional to 81.27, 112.21 and 56.43

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Solution

The fourth proportional to 81.27, 112.21 and 56.43 is: 77.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.27 : 112.21 = 56.43 : x
  2. Step 2: Convert to fraction form
    81.27/112.21 = 56.43/x
  3. Step 3: Cross multiply
    81.27x = 112.21 × 56.43
  4. Step 4: Simplify right side
    81.27x = 6,331.87
  5. Step 5: Solve for x
    x = 6,331.87/81.27
  6. Step 6: Final answer
    x = 77.91

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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.