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Finding the Fourth Proportional to 138.21, 190.62 and 89.09

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Solution

The fourth proportional to 138.21, 190.62 and 89.09 is: 122.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.21 : 190.62 = 89.09 : x
  2. Step 2: Convert to fraction form
    138.21/190.62 = 89.09/x
  3. Step 3: Cross multiply
    138.21x = 190.62 × 89.09
  4. Step 4: Simplify right side
    138.21x = 16,982.34
  5. Step 5: Solve for x
    x = 16,982.34/138.21
  6. Step 6: Final answer
    x = 122.87

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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.