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Finding the Fourth Proportional to 138.20, 190.68 and 89.11

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Solution

The fourth proportional to 138.20, 190.68 and 89.11 is: 122.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.20 : 190.68 = 89.11 : x
  2. Step 2: Convert to fraction form
    138.20/190.68 = 89.11/x
  3. Step 3: Cross multiply
    138.20x = 190.68 × 89.11
  4. Step 4: Simplify right side
    138.20x = 16,991.24
  5. Step 5: Solve for x
    x = 16,991.24/138.20
  6. Step 6: Final answer
    x = 122.94

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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.