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Finding the Fourth Proportional to 8.12, 12.20 and 7.72

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Solution

The fourth proportional to 8.12, 12.20 and 7.72 is: 11.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.12 : 12.20 = 7.72 : x
  2. Step 2: Convert to fraction form
    8.12/12.20 = 7.72/x
  3. Step 3: Cross multiply
    8.12x = 12.20 × 7.72
  4. Step 4: Simplify right side
    8.12x = 94.18
  5. Step 5: Solve for x
    x = 94.18/8.12
  6. Step 6: Final answer
    x = 11.60

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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.