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Finding the Third Proportional to 312.38 and 639.94

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Solution

The third proportional to 312.38 and 639.94 is: 1,310.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.38 : 639.94 = 639.94 : x
  2. Step 2: Convert to fraction form
    312.38/639.94 = 639.94/x
  3. Step 3: Cross multiply
    312.38x = 639.94 × 639.94
  4. Step 4: Simplify right side
    312.38x = 409,520.00
  5. Step 5: Solve for x
    x = 409,520.00/312.38
  6. Step 6: Final answer
    x = 1,310.99

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Why These Related Problems?

These problems maintain the same ratio (2.05) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.