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Finding the Fourth Proportional to 639.42, 882.37 and 390.73

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Solution

The fourth proportional to 639.42, 882.37 and 390.73 is: 539.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.42 : 882.37 = 390.73 : x
  2. Step 2: Convert to fraction form
    639.42/882.37 = 390.73/x
  3. Step 3: Cross multiply
    639.42x = 882.37 × 390.73
  4. Step 4: Simplify right side
    639.42x = 344,768.43
  5. Step 5: Solve for x
    x = 344,768.43/639.42
  6. Step 6: Final answer
    x = 539.19

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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.