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Finding the Fourth Proportional to 408.20, 607.69 and 405.80

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Solution

The fourth proportional to 408.20, 607.69 and 405.80 is: 604.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.20 : 607.69 = 405.80 : x
  2. Step 2: Convert to fraction form
    408.20/607.69 = 405.80/x
  3. Step 3: Cross multiply
    408.20x = 607.69 × 405.80
  4. Step 4: Simplify right side
    408.20x = 246,600.60
  5. Step 5: Solve for x
    x = 246,600.60/408.20
  6. Step 6: Final answer
    x = 604.12

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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.