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Finding the Third Proportional to 121 and 218

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Solution

The third proportional to 121 and 218 is: 392.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    121 : 218 = 218 : x
  2. Step 2: Convert to fraction form
    121/218 = 218/x
  3. Step 3: Cross multiply
    121x = 218 × 218
  4. Step 4: Simplify right side
    121x = 47,524
  5. Step 5: Solve for x
    x = 47,524/121
  6. Step 6: Final answer
    x = 392.76

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Why These Related Problems?

These problems maintain the same ratio (1.80) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.