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Finding the Fourth Proportional to 138.11, 190.55 and 85.64

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Solution

The fourth proportional to 138.11, 190.55 and 85.64 is: 118.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.11 : 190.55 = 85.64 : x
  2. Step 2: Convert to fraction form
    138.11/190.55 = 85.64/x
  3. Step 3: Cross multiply
    138.11x = 190.55 × 85.64
  4. Step 4: Simplify right side
    138.11x = 16,317.32
  5. Step 5: Solve for x
    x = 16,317.32/138.11
  6. Step 6: Final answer
    x = 118.15

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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.