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Finding the Fourth Proportional to 28.43, 42.61 and 20.39

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Solution

The fourth proportional to 28.43, 42.61 and 20.39 is: 30.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.43 : 42.61 = 20.39 : x
  2. Step 2: Convert to fraction form
    28.43/42.61 = 20.39/x
  3. Step 3: Cross multiply
    28.43x = 42.61 × 20.39
  4. Step 4: Simplify right side
    28.43x = 868.63
  5. Step 5: Solve for x
    x = 868.63/28.43
  6. Step 6: Final answer
    x = 30.56

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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.