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Finding the Fourth Proportional to 639.61, 959.39 and 206.75

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Solution

The fourth proportional to 639.61, 959.39 and 206.75 is: 310.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.61 : 959.39 = 206.75 : x
  2. Step 2: Convert to fraction form
    639.61/959.39 = 206.75/x
  3. Step 3: Cross multiply
    639.61x = 959.39 × 206.75
  4. Step 4: Simplify right side
    639.61x = 198,352.85
  5. Step 5: Solve for x
    x = 198,352.85/639.61
  6. Step 6: Final answer
    x = 310.12

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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.