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Finding the Fourth Proportional to 25.91, 38.69 and 20.85

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Solution

The fourth proportional to 25.91, 38.69 and 20.85 is: 31.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    25.91 : 38.69 = 20.85 : x
  2. Step 2: Convert to fraction form
    25.91/38.69 = 20.85/x
  3. Step 3: Cross multiply
    25.91x = 38.69 × 20.85
  4. Step 4: Simplify right side
    25.91x = 806.69
  5. Step 5: Solve for x
    x = 806.69/25.91
  6. Step 6: Final answer
    x = 31.13

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.