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Finding the Fourth Proportional to 8.28, 12.42 and 3.21

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Solution

The fourth proportional to 8.28, 12.42 and 3.21 is: 4.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.28 : 12.42 = 3.21 : x
  2. Step 2: Convert to fraction form
    8.28/12.42 = 3.21/x
  3. Step 3: Cross multiply
    8.28x = 12.42 × 3.21
  4. Step 4: Simplify right side
    8.28x = 39.86
  5. Step 5: Solve for x
    x = 39.86/8.28
  6. Step 6: Final answer
    x = 4.81

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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.