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Finding the Third Proportional to 218.81 and 408.09

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Solution

The third proportional to 218.81 and 408.09 is: 761.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.81 : 408.09 = 408.09 : x
  2. Step 2: Convert to fraction form
    218.81/408.09 = 408.09/x
  3. Step 3: Cross multiply
    218.81x = 408.09 × 408.09
  4. Step 4: Simplify right side
    218.81x = 166,540.51
  5. Step 5: Solve for x
    x = 166,540.51/218.81
  6. Step 6: Final answer
    x = 761.11

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Why These Related Problems?

These problems maintain the same ratio (1.87) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.