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Finding the Fourth Proportional to 5.15, 7.11 and 2.85

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Solution

The fourth proportional to 5.15, 7.11 and 2.85 is: 3.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    5.15 : 7.11 = 2.85 : x
  2. Step 2: Convert to fraction form
    5.15/7.11 = 2.85/x
  3. Step 3: Cross multiply
    5.15x = 7.11 × 2.85
  4. Step 4: Simplify right side
    5.15x = 20.28
  5. Step 5: Solve for x
    x = 20.28/5.15
  6. Step 6: Final answer
    x = 3.94

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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.