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Finding the Third Proportional to 1.81 and 3.91

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Solution

The third proportional to 1.81 and 3.91 is: 8.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1.81 : 3.91 = 3.91 : x
  2. Step 2: Convert to fraction form
    1.81/3.91 = 3.91/x
  3. Step 3: Cross multiply
    1.81x = 3.91 × 3.91
  4. Step 4: Simplify right side
    1.81x = 15.26
  5. Step 5: Solve for x
    x = 15.26/1.81
  6. Step 6: Final answer
    x = 8.42

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Why These Related Problems?

These problems maintain the same ratio (2.16) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.