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Finding the Fourth Proportional to 22.20, 30.48 and 21.78

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Solution

The fourth proportional to 22.20, 30.48 and 21.78 is: 29.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    22.20 : 30.48 = 21.78 : x
  2. Step 2: Convert to fraction form
    22.20/30.48 = 21.78/x
  3. Step 3: Cross multiply
    22.20x = 30.48 × 21.78
  4. Step 4: Simplify right side
    22.20x = 663.85
  5. Step 5: Solve for x
    x = 663.85/22.20
  6. Step 6: Final answer
    x = 29.90

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.