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Finding the Fourth Proportional to 38.70, 57.96 and 20.61

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Solution

The fourth proportional to 38.70, 57.96 and 20.61 is: 30.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.70 : 57.96 = 20.61 : x
  2. Step 2: Convert to fraction form
    38.70/57.96 = 20.61/x
  3. Step 3: Cross multiply
    38.70x = 57.96 × 20.61
  4. Step 4: Simplify right side
    38.70x = 1,194.56
  5. Step 5: Solve for x
    x = 1,194.56/38.70
  6. Step 6: Final answer
    x = 30.87

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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.