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Finding the Fourth Proportional to 403.20, 556.31 and 255.78

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Solution

The fourth proportional to 403.20, 556.31 and 255.78 is: 352.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    403.20 : 556.31 = 255.78 : x
  2. Step 2: Convert to fraction form
    403.20/556.31 = 255.78/x
  3. Step 3: Cross multiply
    403.20x = 556.31 × 255.78
  4. Step 4: Simplify right side
    403.20x = 142,292.97
  5. Step 5: Solve for x
    x = 142,292.97/403.20
  6. Step 6: Final answer
    x = 352.91

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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.