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Finding the Fourth Proportional to 239.38, 359.09 and 85.39

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Solution

The fourth proportional to 239.38, 359.09 and 85.39 is: 128.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    239.38 : 359.09 = 85.39 : x
  2. Step 2: Convert to fraction form
    239.38/359.09 = 85.39/x
  3. Step 3: Cross multiply
    239.38x = 359.09 × 85.39
  4. Step 4: Simplify right side
    239.38x = 30,662.70
  5. Step 5: Solve for x
    x = 30,662.70/239.38
  6. Step 6: Final answer
    x = 128.09

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.