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Finding the Fourth Proportional to 138.18, 207 and 105.75

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Solution

The fourth proportional to 138.18, 207 and 105.75 is: 158.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.18 : 207 = 105.75 : x
  2. Step 2: Convert to fraction form
    138.18/207 = 105.75/x
  3. Step 3: Cross multiply
    138.18x = 207 × 105.75
  4. Step 4: Simplify right side
    138.18x = 21,890.25
  5. Step 5: Solve for x
    x = 21,890.25/138.18
  6. Step 6: Final answer
    x = 158.42

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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.