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Finding the Fourth Proportional to 38.61, 57.91 and 20.58

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Solution

The fourth proportional to 38.61, 57.91 and 20.58 is: 30.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.61 : 57.91 = 20.58 : x
  2. Step 2: Convert to fraction form
    38.61/57.91 = 20.58/x
  3. Step 3: Cross multiply
    38.61x = 57.91 × 20.58
  4. Step 4: Simplify right side
    38.61x = 1,191.68
  5. Step 5: Solve for x
    x = 1,191.68/38.61
  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.