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Finding the Fourth Proportional to 20.38, 28.12 and 11.75

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Solution

The fourth proportional to 20.38, 28.12 and 11.75 is: 16.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.38 : 28.12 = 11.75 : x
  2. Step 2: Convert to fraction form
    20.38/28.12 = 11.75/x
  3. Step 3: Cross multiply
    20.38x = 28.12 × 11.75
  4. Step 4: Simplify right side
    20.38x = 330.38
  5. Step 5: Solve for x
    x = 330.38/20.38
  6. Step 6: Final answer
    x = 16.22

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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.