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Finding the Fourth Proportional to 20.36, 30.38 and 18.91

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Solution

The fourth proportional to 20.36, 30.38 and 18.91 is: 28.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.36 : 30.38 = 18.91 : x
  2. Step 2: Convert to fraction form
    20.36/30.38 = 18.91/x
  3. Step 3: Cross multiply
    20.36x = 30.38 × 18.91
  4. Step 4: Simplify right side
    20.36x = 574.49
  5. Step 5: Solve for x
    x = 574.49/20.36
  6. Step 6: Final answer
    x = 28.22

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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.