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Finding the Fourth Proportional to 15.09, 20.85 and 11.88

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Solution

The fourth proportional to 15.09, 20.85 and 11.88 is: 16.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.09 : 20.85 = 11.88 : x
  2. Step 2: Convert to fraction form
    15.09/20.85 = 11.88/x
  3. Step 3: Cross multiply
    15.09x = 20.85 × 11.88
  4. Step 4: Simplify right side
    15.09x = 247.70
  5. Step 5: Solve for x
    x = 247.70/15.09
  6. Step 6: Final answer
    x = 16.41

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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.