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Finding the Fourth Proportional to 138.25, 190.64 and 108.69

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Solution

The fourth proportional to 138.25, 190.64 and 108.69 is: 149.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.25 : 190.64 = 108.69 : x
  2. Step 2: Convert to fraction form
    138.25/190.64 = 108.69/x
  3. Step 3: Cross multiply
    138.25x = 190.64 × 108.69
  4. Step 4: Simplify right side
    138.25x = 20,720.66
  5. Step 5: Solve for x
    x = 20,720.66/138.25
  6. Step 6: Final answer
    x = 149.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.