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Finding the Fourth Proportional to 639.84, 959.28 and 331.56

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Solution

The fourth proportional to 639.84, 959.28 and 331.56 is: 497.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.84 : 959.28 = 331.56 : x
  2. Step 2: Convert to fraction form
    639.84/959.28 = 331.56/x
  3. Step 3: Cross multiply
    639.84x = 959.28 × 331.56
  4. Step 4: Simplify right side
    639.84x = 318,058.88
  5. Step 5: Solve for x
    x = 318,058.88/639.84
  6. Step 6: Final answer
    x = 497.09

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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.