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Finding the Fourth Proportional to 168.21, 231.90 and 138.57

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Solution

The fourth proportional to 168.21, 231.90 and 138.57 is: 191.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    168.21 : 231.90 = 138.57 : x
  2. Step 2: Convert to fraction form
    168.21/231.90 = 138.57/x
  3. Step 3: Cross multiply
    168.21x = 231.90 × 138.57
  4. Step 4: Simplify right side
    168.21x = 32,134.38
  5. Step 5: Solve for x
    x = 32,134.38/168.21
  6. Step 6: Final answer
    x = 191.04

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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.