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Finding the Fourth Proportional to 8.21, 12.40 and 8.12

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Solution

The fourth proportional to 8.21, 12.40 and 8.12 is: 12.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.21 : 12.40 = 8.12 : x
  2. Step 2: Convert to fraction form
    8.21/12.40 = 8.12/x
  3. Step 3: Cross multiply
    8.21x = 12.40 × 8.12
  4. Step 4: Simplify right side
    8.21x = 100.70
  5. Step 5: Solve for x
    x = 100.70/8.21
  6. Step 6: Final answer
    x = 12.27

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.