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Finding the Fourth Proportional to 69.78, 103.68 and 67.62

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Solution

The fourth proportional to 69.78, 103.68 and 67.62 is: 100.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.78 : 103.68 = 67.62 : x
  2. Step 2: Convert to fraction form
    69.78/103.68 = 67.62/x
  3. Step 3: Cross multiply
    69.78x = 103.68 × 67.62
  4. Step 4: Simplify right side
    69.78x = 7,010.84
  5. Step 5: Solve for x
    x = 7,010.84/69.78
  6. Step 6: Final answer
    x = 100.47

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.