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Finding the Fourth Proportional to 639.41, 959.20 and 206.42

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Solution

The fourth proportional to 639.41, 959.20 and 206.42 is: 309.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.41 : 959.20 = 206.42 : x
  2. Step 2: Convert to fraction form
    639.41/959.20 = 206.42/x
  3. Step 3: Cross multiply
    639.41x = 959.20 × 206.42
  4. Step 4: Simplify right side
    639.41x = 197,992.75
  5. Step 5: Solve for x
    x = 197,992.75/639.41
  6. Step 6: Final answer
    x = 309.65

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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.