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Finding the Fourth Proportional to 16.81, 25.21 and 7.80

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Solution

The fourth proportional to 16.81, 25.21 and 7.80 is: 11.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    16.81 : 25.21 = 7.80 : x
  2. Step 2: Convert to fraction form
    16.81/25.21 = 7.80/x
  3. Step 3: Cross multiply
    16.81x = 25.21 × 7.80
  4. Step 4: Simplify right side
    16.81x = 196.55
  5. Step 5: Solve for x
    x = 196.55/16.81
  6. Step 6: Final answer
    x = 11.69

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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.