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Finding the Fourth Proportional to 138.13, 190.54 and 85.69

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Solution

The fourth proportional to 138.13, 190.54 and 85.69 is: 118.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.13 : 190.54 = 85.69 : x
  2. Step 2: Convert to fraction form
    138.13/190.54 = 85.69/x
  3. Step 3: Cross multiply
    138.13x = 190.54 × 85.69
  4. Step 4: Simplify right side
    138.13x = 16,327.37
  5. Step 5: Solve for x
    x = 16,327.37/138.13
  6. Step 6: Final answer
    x = 118.20

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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.