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Finding the Fourth Proportional to 3.11, 4.28 and 2.81

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Solution

The fourth proportional to 3.11, 4.28 and 2.81 is: 3.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    3.11 : 4.28 = 2.81 : x
  2. Step 2: Convert to fraction form
    3.11/4.28 = 2.81/x
  3. Step 3: Cross multiply
    3.11x = 4.28 × 2.81
  4. Step 4: Simplify right side
    3.11x = 11.99
  5. Step 5: Solve for x
    x = 11.99/3.11
  6. Step 6: Final answer
    x = 3.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.