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Finding the Fourth Proportional to 639.99, 883.49 and 391.41

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Solution

The fourth proportional to 639.99, 883.49 and 391.41 is: 540.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.99 : 883.49 = 391.41 : x
  2. Step 2: Convert to fraction form
    639.99/883.49 = 391.41/x
  3. Step 3: Cross multiply
    639.99x = 883.49 × 391.41
  4. Step 4: Simplify right side
    639.99x = 345,804.86
  5. Step 5: Solve for x
    x = 345,804.86/639.99
  6. Step 6: Final answer
    x = 540.33

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.