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Finding the Third Proportional to 3.91 and 5.81

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Solution

The third proportional to 3.91 and 5.81 is: 8.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    3.91 : 5.81 = 5.81 : x
  2. Step 2: Convert to fraction form
    3.91/5.81 = 5.81/x
  3. Step 3: Cross multiply
    3.91x = 5.81 × 5.81
  4. Step 4: Simplify right side
    3.91x = 33.81
  5. Step 5: Solve for x
    x = 33.81/3.91
  6. Step 6: Final answer
    x = 8.66

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.