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Finding the Third Proportional to 30.85 and 39.87

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Solution

The third proportional to 30.85 and 39.87 is: 51.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.85 : 39.87 = 39.87 : x
  2. Step 2: Convert to fraction form
    30.85/39.87 = 39.87/x
  3. Step 3: Cross multiply
    30.85x = 39.87 × 39.87
  4. Step 4: Simplify right side
    30.85x = 1,589.39
  5. Step 5: Solve for x
    x = 1,589.39/30.85
  6. Step 6: Final answer
    x = 51.52

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Why These Related Problems?

These problems maintain the same ratio (1.29) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.