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Finding the Third Proportional to 7.85 and 20.61

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Solution

The third proportional to 7.85 and 20.61 is: 54.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.85 : 20.61 = 20.61 : x
  2. Step 2: Convert to fraction form
    7.85/20.61 = 20.61/x
  3. Step 3: Cross multiply
    7.85x = 20.61 × 20.61
  4. Step 4: Simplify right side
    7.85x = 424.61
  5. Step 5: Solve for x
    x = 424.61/7.85
  6. Step 6: Final answer
    x = 54.11

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Why These Related Problems?

These problems maintain the same ratio (2.63) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.