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Finding the Fourth Proportional to 639.49, 959.17 and 249.78

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Solution

The fourth proportional to 639.49, 959.17 and 249.78 is: 374.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.49 : 959.17 = 249.78 : x
  2. Step 2: Convert to fraction form
    639.49/959.17 = 249.78/x
  3. Step 3: Cross multiply
    639.49x = 959.17 × 249.78
  4. Step 4: Simplify right side
    639.49x = 239,581.48
  5. Step 5: Solve for x
    x = 239,581.48/639.49
  6. Step 6: Final answer
    x = 374.64

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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.