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Finding the Fourth Proportional to 408.80, 613.20 and 255.20

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Solution

The fourth proportional to 408.80, 613.20 and 255.20 is: 382.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.80 : 613.20 = 255.20 : x
  2. Step 2: Convert to fraction form
    408.80/613.20 = 255.20/x
  3. Step 3: Cross multiply
    408.80x = 613.20 × 255.20
  4. Step 4: Simplify right side
    408.80x = 156,488.64
  5. Step 5: Solve for x
    x = 156,488.64/408.80
  6. Step 6: Final answer
    x = 382.80

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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.