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Finding the Fourth Proportional to 639.82, 883.07 and 391.35

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Solution

The fourth proportional to 639.82, 883.07 and 391.35 is: 540.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.82 : 883.07 = 391.35 : x
  2. Step 2: Convert to fraction form
    639.82/883.07 = 391.35/x
  3. Step 3: Cross multiply
    639.82x = 883.07 × 391.35
  4. Step 4: Simplify right side
    639.82x = 345,589.44
  5. Step 5: Solve for x
    x = 345,589.44/639.82
  6. Step 6: Final answer
    x = 540.14

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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.