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Finding the Fourth Proportional to 68.78, 94.91 and 39.66

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Solution

The fourth proportional to 68.78, 94.91 and 39.66 is: 54.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.78 : 94.91 = 39.66 : x
  2. Step 2: Convert to fraction form
    68.78/94.91 = 39.66/x
  3. Step 3: Cross multiply
    68.78x = 94.91 × 39.66
  4. Step 4: Simplify right side
    68.78x = 3,763.58
  5. Step 5: Solve for x
    x = 3,763.58/68.78
  6. Step 6: Final answer
    x = 54.72

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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.