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Finding the Third Proportional to 39.87 and 82.90

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Solution

The third proportional to 39.87 and 82.90 is: 172.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.87 : 82.90 = 82.90 : x
  2. Step 2: Convert to fraction form
    39.87/82.90 = 82.90/x
  3. Step 3: Cross multiply
    39.87x = 82.90 × 82.90
  4. Step 4: Simplify right side
    39.87x = 6,872.15
  5. Step 5: Solve for x
    x = 6,872.15/39.87
  6. Step 6: Final answer
    x = 172.38

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Why These Related Problems?

These problems maintain the same ratio (2.08) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.