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Finding the Fourth Proportional to 639.69, 959.54 and 206.85

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Solution

The fourth proportional to 639.69, 959.54 and 206.85 is: 310.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.69 : 959.54 = 206.85 : x
  2. Step 2: Convert to fraction form
    639.69/959.54 = 206.85/x
  3. Step 3: Cross multiply
    639.69x = 959.54 × 206.85
  4. Step 4: Simplify right side
    639.69x = 198,480.85
  5. Step 5: Solve for x
    x = 198,480.85/639.69
  6. Step 6: Final answer
    x = 310.28

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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.