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Finding the Fourth Proportional to 28.28, 42.36 and 20.55

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Solution

The fourth proportional to 28.28, 42.36 and 20.55 is: 30.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.28 : 42.36 = 20.55 : x
  2. Step 2: Convert to fraction form
    28.28/42.36 = 20.55/x
  3. Step 3: Cross multiply
    28.28x = 42.36 × 20.55
  4. Step 4: Simplify right side
    28.28x = 870.50
  5. Step 5: Solve for x
    x = 870.50/28.28
  6. Step 6: Final answer
    x = 30.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.