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Finding the Fourth Proportional to 22.20, 30.68 and 20.85

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Solution

The fourth proportional to 22.20, 30.68 and 20.85 is: 28.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    22.20 : 30.68 = 20.85 : x
  2. Step 2: Convert to fraction form
    22.20/30.68 = 20.85/x
  3. Step 3: Cross multiply
    22.20x = 30.68 × 20.85
  4. Step 4: Simplify right side
    22.20x = 639.68
  5. Step 5: Solve for x
    x = 639.68/22.20
  6. Step 6: Final answer
    x = 28.81

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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.