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Finding the Fourth Proportional to 138.20, 190.62 and 91.58

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Solution

The fourth proportional to 138.20, 190.62 and 91.58 is: 126.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.20 : 190.62 = 91.58 : x
  2. Step 2: Convert to fraction form
    138.20/190.62 = 91.58/x
  3. Step 3: Cross multiply
    138.20x = 190.62 × 91.58
  4. Step 4: Simplify right side
    138.20x = 17,456.03
  5. Step 5: Solve for x
    x = 17,456.03/138.20
  6. Step 6: Final answer
    x = 126.31

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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.