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Finding the Fourth Proportional to 138.51, 207.78 and 51.85

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Solution

The fourth proportional to 138.51, 207.78 and 51.85 is: 77.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.51 : 207.78 = 51.85 : x
  2. Step 2: Convert to fraction form
    138.51/207.78 = 51.85/x
  3. Step 3: Cross multiply
    138.51x = 207.78 × 51.85
  4. Step 4: Simplify right side
    138.51x = 10,773.39
  5. Step 5: Solve for x
    x = 10,773.39/138.51
  6. Step 6: Final answer
    x = 77.78

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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.