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Finding the Fourth Proportional to 13.58, 20.31 and 11.87

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Solution

The fourth proportional to 13.58, 20.31 and 11.87 is: 17.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.58 : 20.31 = 11.87 : x
  2. Step 2: Convert to fraction form
    13.58/20.31 = 11.87/x
  3. Step 3: Cross multiply
    13.58x = 20.31 × 11.87
  4. Step 4: Simplify right side
    13.58x = 240.98
  5. Step 5: Solve for x
    x = 240.98/13.58
  6. Step 6: Final answer
    x = 17.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.