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Finding the Fourth Proportional to 321.05, 479.39 and 255.31

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Solution

The fourth proportional to 321.05, 479.39 and 255.31 is: 381.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.05 : 479.39 = 255.31 : x
  2. Step 2: Convert to fraction form
    321.05/479.39 = 255.31/x
  3. Step 3: Cross multiply
    321.05x = 479.39 × 255.31
  4. Step 4: Simplify right side
    321.05x = 122,393.06
  5. Step 5: Solve for x
    x = 122,393.06/321.05
  6. Step 6: Final answer
    x = 381.23

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.