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Finding the Fourth Proportional to 639.57, 959.31 and 206.70

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Solution

The fourth proportional to 639.57, 959.31 and 206.70 is: 310.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.57 : 959.31 = 206.70 : x
  2. Step 2: Convert to fraction form
    639.57/959.31 = 206.70/x
  3. Step 3: Cross multiply
    639.57x = 959.31 × 206.70
  4. Step 4: Simplify right side
    639.57x = 198,289.38
  5. Step 5: Solve for x
    x = 198,289.38/639.57
  6. Step 6: Final answer
    x = 310.04

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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.