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Finding the Fourth Proportional to 20.81, 28.72 and 12.19

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Solution

The fourth proportional to 20.81, 28.72 and 12.19 is: 16.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.81 : 28.72 = 12.19 : x
  2. Step 2: Convert to fraction form
    20.81/28.72 = 12.19/x
  3. Step 3: Cross multiply
    20.81x = 28.72 × 12.19
  4. Step 4: Simplify right side
    20.81x = 350.10
  5. Step 5: Solve for x
    x = 350.10/20.81
  6. Step 6: Final answer
    x = 16.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.