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Finding the Fourth Proportional to 408.88, 612.78 and 287.20

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Solution

The fourth proportional to 408.88, 612.78 and 287.20 is: 430.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.88 : 612.78 = 287.20 : x
  2. Step 2: Convert to fraction form
    408.88/612.78 = 287.20/x
  3. Step 3: Cross multiply
    408.88x = 612.78 × 287.20
  4. Step 4: Simplify right side
    408.88x = 175,990.42
  5. Step 5: Solve for x
    x = 175,990.42/408.88
  6. Step 6: Final answer
    x = 430.42

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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.