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Finding the Fourth Proportional to 16.81, 23.20 and 9.90

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Solution

The fourth proportional to 16.81, 23.20 and 9.90 is: 13.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    16.81 : 23.20 = 9.90 : x
  2. Step 2: Convert to fraction form
    16.81/23.20 = 9.90/x
  3. Step 3: Cross multiply
    16.81x = 23.20 × 9.90
  4. Step 4: Simplify right side
    16.81x = 229.66
  5. Step 5: Solve for x
    x = 229.66/16.81
  6. Step 6: Final answer
    x = 13.66

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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.