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Finding the Fourth Proportional to 138.12, 190.65 and 82.87

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Solution

The fourth proportional to 138.12, 190.65 and 82.87 is: 114.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.12 : 190.65 = 82.87 : x
  2. Step 2: Convert to fraction form
    138.12/190.65 = 82.87/x
  3. Step 3: Cross multiply
    138.12x = 190.65 × 82.87
  4. Step 4: Simplify right side
    138.12x = 15,799.17
  5. Step 5: Solve for x
    x = 15,799.17/138.12
  6. Step 6: Final answer
    x = 114.39

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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.