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Finding the Fourth Proportional to 8.21, 12.31 and 2.86

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Solution

The fourth proportional to 8.21, 12.31 and 2.86 is: 4.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.21 : 12.31 = 2.86 : x
  2. Step 2: Convert to fraction form
    8.21/12.31 = 2.86/x
  3. Step 3: Cross multiply
    8.21x = 12.31 × 2.86
  4. Step 4: Simplify right side
    8.21x = 35.17
  5. Step 5: Solve for x
    x = 35.17/8.21
  6. Step 6: Final answer
    x = 4.29

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.