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Finding the Fourth Proportional to 27.85, 38.42 and 20.56

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Solution

The fourth proportional to 27.85, 38.42 and 20.56 is: 28.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    27.85 : 38.42 = 20.56 : x
  2. Step 2: Convert to fraction form
    27.85/38.42 = 20.56/x
  3. Step 3: Cross multiply
    27.85x = 38.42 × 20.56
  4. Step 4: Simplify right side
    27.85x = 789.92
  5. Step 5: Solve for x
    x = 789.92/27.85
  6. Step 6: Final answer
    x = 28.36

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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.