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Finding the Fourth Proportional to 20.36, 28.09 and 11.15

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Solution

The fourth proportional to 20.36, 28.09 and 11.15 is: 15.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.36 : 28.09 = 11.15 : x
  2. Step 2: Convert to fraction form
    20.36/28.09 = 11.15/x
  3. Step 3: Cross multiply
    20.36x = 28.09 × 11.15
  4. Step 4: Simplify right side
    20.36x = 313.10
  5. Step 5: Solve for x
    x = 313.10/20.36
  6. Step 6: Final answer
    x = 15.38

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.