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Finding the Fourth Proportional to 9.91, 14.81 and 8.20

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Solution

The fourth proportional to 9.91, 14.81 and 8.20 is: 12.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    9.91 : 14.81 = 8.20 : x
  2. Step 2: Convert to fraction form
    9.91/14.81 = 8.20/x
  3. Step 3: Cross multiply
    9.91x = 14.81 × 8.20
  4. Step 4: Simplify right side
    9.91x = 121.42
  5. Step 5: Solve for x
    x = 121.42/9.91
  6. Step 6: Final answer
    x = 12.25

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.