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Finding the Fourth Proportional to 138.23, 190.71 and 85.81

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Solution

The fourth proportional to 138.23, 190.71 and 85.81 is: 118.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.23 : 190.71 = 85.81 : x
  2. Step 2: Convert to fraction form
    138.23/190.71 = 85.81/x
  3. Step 3: Cross multiply
    138.23x = 190.71 × 85.81
  4. Step 4: Simplify right side
    138.23x = 16,364.87
  5. Step 5: Solve for x
    x = 16,364.87/138.23
  6. Step 6: Final answer
    x = 118.39

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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.