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Finding the Third Proportional to 87.75 and 121.78

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Solution

The third proportional to 87.75 and 121.78 is: 169.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.75 : 121.78 = 121.78 : x
  2. Step 2: Convert to fraction form
    87.75/121.78 = 121.78/x
  3. Step 3: Cross multiply
    87.75x = 121.78 × 121.78
  4. Step 4: Simplify right side
    87.75x = 14,830.67
  5. Step 5: Solve for x
    x = 14,830.67/87.75
  6. Step 6: Final answer
    x = 169.01

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.