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Finding the Third Proportional to 311.06 and 642.38

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Solution

The third proportional to 311.06 and 642.38 is: 1,326.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.06 : 642.38 = 642.38 : x
  2. Step 2: Convert to fraction form
    311.06/642.38 = 642.38/x
  3. Step 3: Cross multiply
    311.06x = 642.38 × 642.38
  4. Step 4: Simplify right side
    311.06x = 412,645.64
  5. Step 5: Solve for x
    x = 412,645.64/311.06
  6. Step 6: Final answer
    x = 1,326.57

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Why These Related Problems?

These problems maintain the same ratio (2.07) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.