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Finding the Fourth Proportional to 138.43, 190.91 and 113.72

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Solution

The fourth proportional to 138.43, 190.91 and 113.72 is: 156.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.43 : 190.91 = 113.72 : x
  2. Step 2: Convert to fraction form
    138.43/190.91 = 113.72/x
  3. Step 3: Cross multiply
    138.43x = 190.91 × 113.72
  4. Step 4: Simplify right side
    138.43x = 21,709.72
  5. Step 5: Solve for x
    x = 21,709.72/138.43
  6. Step 6: Final answer
    x = 156.83

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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.