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Finding the Third Proportional to 77.90 and 122.21

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Solution

The third proportional to 77.90 and 122.21 is: 191.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.90 : 122.21 = 122.21 : x
  2. Step 2: Convert to fraction form
    77.90/122.21 = 122.21/x
  3. Step 3: Cross multiply
    77.90x = 122.21 × 122.21
  4. Step 4: Simplify right side
    77.90x = 14,935.75
  5. Step 5: Solve for x
    x = 14,935.75/77.90
  6. Step 6: Final answer
    x = 191.74

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Why These Related Problems?

These problems maintain the same ratio (1.57) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.