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Finding the Fourth Proportional to 138.85, 208.38 and 102.88

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Solution

The fourth proportional to 138.85, 208.38 and 102.88 is: 154.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.85 : 208.38 = 102.88 : x
  2. Step 2: Convert to fraction form
    138.85/208.38 = 102.88/x
  3. Step 3: Cross multiply
    138.85x = 208.38 × 102.88
  4. Step 4: Simplify right side
    138.85x = 21,438.13
  5. Step 5: Solve for x
    x = 21,438.13/138.85
  6. Step 6: Final answer
    x = 154.40

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These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.