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Finding the Fourth Proportional to 81.29, 112.13 and 56.79

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Solution

The fourth proportional to 81.29, 112.13 and 56.79 is: 78.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.29 : 112.13 = 56.79 : x
  2. Step 2: Convert to fraction form
    81.29/112.13 = 56.79/x
  3. Step 3: Cross multiply
    81.29x = 112.13 × 56.79
  4. Step 4: Simplify right side
    81.29x = 6,367.30
  5. Step 5: Solve for x
    x = 6,367.30/81.29
  6. Step 6: Final answer
    x = 78.33

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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.