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Finding the Fourth Proportional to 69.78, 105.07 and 55.42

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Solution

The fourth proportional to 69.78, 105.07 and 55.42 is: 83.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.78 : 105.07 = 55.42 : x
  2. Step 2: Convert to fraction form
    69.78/105.07 = 55.42/x
  3. Step 3: Cross multiply
    69.78x = 105.07 × 55.42
  4. Step 4: Simplify right side
    69.78x = 5,822.98
  5. Step 5: Solve for x
    x = 5,822.98/69.78
  6. Step 6: Final answer
    x = 83.45

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.