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Finding the Fourth Proportional to 664.78, 996.87 and 390.96

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Solution

The fourth proportional to 664.78, 996.87 and 390.96 is: 586.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.78 : 996.87 = 390.96 : x
  2. Step 2: Convert to fraction form
    664.78/996.87 = 390.96/x
  3. Step 3: Cross multiply
    664.78x = 996.87 × 390.96
  4. Step 4: Simplify right side
    664.78x = 389,736.30
  5. Step 5: Solve for x
    x = 389,736.30/664.78
  6. Step 6: Final answer
    x = 586.26

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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.