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Finding the Fourth Proportional to 665.78, 998.37 and 391.97

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Solution

The fourth proportional to 665.78, 998.37 and 391.97 is: 587.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.78 : 998.37 = 391.97 : x
  2. Step 2: Convert to fraction form
    665.78/998.37 = 391.97/x
  3. Step 3: Cross multiply
    665.78x = 998.37 × 391.97
  4. Step 4: Simplify right side
    665.78x = 391,324.14
  5. Step 5: Solve for x
    x = 391,324.14/665.78
  6. Step 6: Final answer
    x = 587.77

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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.