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Finding the Fourth Proportional to 68.78, 94.92 and 39.68

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Solution

The fourth proportional to 68.78, 94.92 and 39.68 is: 54.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.78 : 94.92 = 39.68 : x
  2. Step 2: Convert to fraction form
    68.78/94.92 = 39.68/x
  3. Step 3: Cross multiply
    68.78x = 94.92 × 39.68
  4. Step 4: Simplify right side
    68.78x = 3,766.43
  5. Step 5: Solve for x
    x = 3,766.43/68.78
  6. Step 6: Final answer
    x = 54.76

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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.