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Finding the Fourth Proportional to 69.78, 104.74 and 45.42

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Solution

The fourth proportional to 69.78, 104.74 and 45.42 is: 68.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.78 : 104.74 = 45.42 : x
  2. Step 2: Convert to fraction form
    69.78/104.74 = 45.42/x
  3. Step 3: Cross multiply
    69.78x = 104.74 × 45.42
  4. Step 4: Simplify right side
    69.78x = 4,757.29
  5. Step 5: Solve for x
    x = 4,757.29/69.78
  6. Step 6: Final answer
    x = 68.18

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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.