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Finding the Fourth Proportional to 20.90, 31.29 and 16.61

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Solution

The fourth proportional to 20.90, 31.29 and 16.61 is: 24.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.90 : 31.29 = 16.61 : x
  2. Step 2: Convert to fraction form
    20.90/31.29 = 16.61/x
  3. Step 3: Cross multiply
    20.90x = 31.29 × 16.61
  4. Step 4: Simplify right side
    20.90x = 519.57
  5. Step 5: Solve for x
    x = 519.57/20.90
  6. Step 6: Final answer
    x = 24.87

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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.