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Finding the Fourth Proportional to 20.40, 28.02 and 17.31

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Solution

The fourth proportional to 20.40, 28.02 and 17.31 is: 23.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.40 : 28.02 = 17.31 : x
  2. Step 2: Convert to fraction form
    20.40/28.02 = 17.31/x
  3. Step 3: Cross multiply
    20.40x = 28.02 × 17.31
  4. Step 4: Simplify right side
    20.40x = 485.03
  5. Step 5: Solve for x
    x = 485.03/20.40
  6. Step 6: Final answer
    x = 23.78

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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.