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Finding the Fourth Proportional to 138.12, 207.20 and 51.44

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Solution

The fourth proportional to 138.12, 207.20 and 51.44 is: 77.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.12 : 207.20 = 51.44 : x
  2. Step 2: Convert to fraction form
    138.12/207.20 = 51.44/x
  3. Step 3: Cross multiply
    138.12x = 207.20 × 51.44
  4. Step 4: Simplify right side
    138.12x = 10,658.37
  5. Step 5: Solve for x
    x = 10,658.37/138.12
  6. Step 6: Final answer
    x = 77.17

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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.