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Finding the Third Proportional to 311.41 and 642.45

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Solution

The third proportional to 311.41 and 642.45 is: 1,325.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.41 : 642.45 = 642.45 : x
  2. Step 2: Convert to fraction form
    311.41/642.45 = 642.45/x
  3. Step 3: Cross multiply
    311.41x = 642.45 × 642.45
  4. Step 4: Simplify right side
    311.41x = 412,735.98
  5. Step 5: Solve for x
    x = 412,735.98/311.41
  6. Step 6: Final answer
    x = 1,325.36

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Why These Related Problems?

These problems maintain the same ratio (2.06) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.