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Finding the Fourth Proportional to 639.28, 958.90 and 206.46

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Solution

The fourth proportional to 639.28, 958.90 and 206.46 is: 309.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.28 : 958.90 = 206.46 : x
  2. Step 2: Convert to fraction form
    639.28/958.90 = 206.46/x
  3. Step 3: Cross multiply
    639.28x = 958.90 × 206.46
  4. Step 4: Simplify right side
    639.28x = 197,974.49
  5. Step 5: Solve for x
    x = 197,974.49/639.28
  6. Step 6: Final answer
    x = 309.68

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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.