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Finding the Fourth Proportional to 13.98, 20.99 and 8.91

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Solution

The fourth proportional to 13.98, 20.99 and 8.91 is: 13.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.98 : 20.99 = 8.91 : x
  2. Step 2: Convert to fraction form
    13.98/20.99 = 8.91/x
  3. Step 3: Cross multiply
    13.98x = 20.99 × 8.91
  4. Step 4: Simplify right side
    13.98x = 186.98
  5. Step 5: Solve for x
    x = 186.98/13.98
  6. Step 6: Final answer
    x = 13.37

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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.