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Finding the Third Proportional to 121.75 and 216.75

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Solution

The third proportional to 121.75 and 216.75 is: 385.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.75 : 216.75 = 216.75 : x
  2. Step 2: Convert to fraction form
    121.75/216.75 = 216.75/x
  3. Step 3: Cross multiply
    121.75x = 216.75 × 216.75
  4. Step 4: Simplify right side
    121.75x = 46,980.56
  5. Step 5: Solve for x
    x = 46,980.56/121.75
  6. Step 6: Final answer
    x = 385.88

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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.