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Finding the Fourth Proportional to 31.87, 47.81 and 25.89

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Solution

The fourth proportional to 31.87, 47.81 and 25.89 is: 38.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.87 : 47.81 = 25.89 : x
  2. Step 2: Convert to fraction form
    31.87/47.81 = 25.89/x
  3. Step 3: Cross multiply
    31.87x = 47.81 × 25.89
  4. Step 4: Simplify right side
    31.87x = 1,237.80
  5. Step 5: Solve for x
    x = 1,237.80/31.87
  6. Step 6: Final answer
    x = 38.84

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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.