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Finding the Fourth Proportional to 20.85, 31.29 and 19.83

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Solution

The fourth proportional to 20.85, 31.29 and 19.83 is: 29.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.85 : 31.29 = 19.83 : x
  2. Step 2: Convert to fraction form
    20.85/31.29 = 19.83/x
  3. Step 3: Cross multiply
    20.85x = 31.29 × 19.83
  4. Step 4: Simplify right side
    20.85x = 620.48
  5. Step 5: Solve for x
    x = 620.48/20.85
  6. Step 6: Final answer
    x = 29.76

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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.