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Finding the Fourth Proportional to 20.84, 31.23 and 11.21

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Solution

The fourth proportional to 20.84, 31.23 and 11.21 is: 16.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.84 : 31.23 = 11.21 : x
  2. Step 2: Convert to fraction form
    20.84/31.23 = 11.21/x
  3. Step 3: Cross multiply
    20.84x = 31.23 × 11.21
  4. Step 4: Simplify right side
    20.84x = 349.93
  5. Step 5: Solve for x
    x = 349.93/20.84
  6. Step 6: Final answer
    x = 16.80

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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.