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Finding the Fourth Proportional to 408.64, 612.78 and 287.68

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Solution

The fourth proportional to 408.64, 612.78 and 287.68 is: 431.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.64 : 612.78 = 287.68 : x
  2. Step 2: Convert to fraction form
    408.64/612.78 = 287.68/x
  3. Step 3: Cross multiply
    408.64x = 612.78 × 287.68
  4. Step 4: Simplify right side
    408.64x = 176,284.55
  5. Step 5: Solve for x
    x = 176,284.55/408.64
  6. Step 6: Final answer
    x = 431.39

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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.