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Finding the Fourth Proportional to 305.50, 421.31 and 239.89

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Solution

The fourth proportional to 305.50, 421.31 and 239.89 is: 330.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.50 : 421.31 = 239.89 : x
  2. Step 2: Convert to fraction form
    305.50/421.31 = 239.89/x
  3. Step 3: Cross multiply
    305.50x = 421.31 × 239.89
  4. Step 4: Simplify right side
    305.50x = 101,067.54
  5. Step 5: Solve for x
    x = 101,067.54/305.50
  6. Step 6: Final answer
    x = 330.83

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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.