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Finding the Fourth Proportional to 20.40, 30.36 and 20.09

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Solution

The fourth proportional to 20.40, 30.36 and 20.09 is: 29.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.40 : 30.36 = 20.09 : x
  2. Step 2: Convert to fraction form
    20.40/30.36 = 20.09/x
  3. Step 3: Cross multiply
    20.40x = 30.36 × 20.09
  4. Step 4: Simplify right side
    20.40x = 610.08
  5. Step 5: Solve for x
    x = 610.08/20.40
  6. Step 6: Final answer
    x = 29.91

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.