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Finding the Third Proportional to 122.81 and 218.91

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Solution

The third proportional to 122.81 and 218.91 is: 390.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.81 : 218.91 = 218.91 : x
  2. Step 2: Convert to fraction form
    122.81/218.91 = 218.91/x
  3. Step 3: Cross multiply
    122.81x = 218.91 × 218.91
  4. Step 4: Simplify right side
    122.81x = 47,919.95
  5. Step 5: Solve for x
    x = 47,919.95/122.81
  6. Step 6: Final answer
    x = 390.19

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Why These Related Problems?

These problems maintain the same ratio (1.78) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.