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Finding the Fourth Proportional to 69.78, 104.40 and 67.80

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Solution

The fourth proportional to 69.78, 104.40 and 67.80 is: 101.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.78 : 104.40 = 67.80 : x
  2. Step 2: Convert to fraction form
    69.78/104.40 = 67.80/x
  3. Step 3: Cross multiply
    69.78x = 104.40 × 67.80
  4. Step 4: Simplify right side
    69.78x = 7,078.32
  5. Step 5: Solve for x
    x = 7,078.32/69.78
  6. Step 6: Final answer
    x = 101.44

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.