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Finding the Fourth Proportional to 639.89, 882.43 and 387.76

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Solution

The fourth proportional to 639.89, 882.43 and 387.76 is: 534.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.89 : 882.43 = 387.76 : x
  2. Step 2: Convert to fraction form
    639.89/882.43 = 387.76/x
  3. Step 3: Cross multiply
    639.89x = 882.43 × 387.76
  4. Step 4: Simplify right side
    639.89x = 342,171.06
  5. Step 5: Solve for x
    x = 342,171.06/639.89
  6. Step 6: Final answer
    x = 534.73

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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.