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Finding the Third Proportional to 121.88 and 217.75

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Solution

The third proportional to 121.88 and 217.75 is: 389.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.88 : 217.75 = 217.75 : x
  2. Step 2: Convert to fraction form
    121.88/217.75 = 217.75/x
  3. Step 3: Cross multiply
    121.88x = 217.75 × 217.75
  4. Step 4: Simplify right side
    121.88x = 47,415.06
  5. Step 5: Solve for x
    x = 47,415.06/121.88
  6. Step 6: Final answer
    x = 389.05

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Why These Related Problems?

These problems maintain the same ratio (1.79) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.