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Finding the Fourth Proportional to 20.85, 31.39 and 16.39

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Solution

The fourth proportional to 20.85, 31.39 and 16.39 is: 24.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.85 : 31.39 = 16.39 : x
  2. Step 2: Convert to fraction form
    20.85/31.39 = 16.39/x
  3. Step 3: Cross multiply
    20.85x = 31.39 × 16.39
  4. Step 4: Simplify right side
    20.85x = 514.48
  5. Step 5: Solve for x
    x = 514.48/20.85
  6. Step 6: Final answer
    x = 24.68

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.