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Finding the Fourth Proportional to 231.86, 319.91 and 138.64

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Solution

The fourth proportional to 231.86, 319.91 and 138.64 is: 191.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    231.86 : 319.91 = 138.64 : x
  2. Step 2: Convert to fraction form
    231.86/319.91 = 138.64/x
  3. Step 3: Cross multiply
    231.86x = 319.91 × 138.64
  4. Step 4: Simplify right side
    231.86x = 44,350.72
  5. Step 5: Solve for x
    x = 44,350.72/231.86
  6. Step 6: Final answer
    x = 191.28

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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.