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Finding the Third Proportional to 490.50 and 641.75

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Solution

The third proportional to 490.50 and 641.75 is: 839.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    490.50 : 641.75 = 641.75 : x
  2. Step 2: Convert to fraction form
    490.50/641.75 = 641.75/x
  3. Step 3: Cross multiply
    490.50x = 641.75 × 641.75
  4. Step 4: Simplify right side
    490.50x = 411,843.06
  5. Step 5: Solve for x
    x = 411,843.06/490.50
  6. Step 6: Final answer
    x = 839.64

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Why These Related Problems?

These problems maintain the same ratio (1.31) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.