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Finding the Fourth Proportional to 31.85, 47.79 and 13.83

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Solution

The fourth proportional to 31.85, 47.79 and 13.83 is: 20.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.85 : 47.79 = 13.83 : x
  2. Step 2: Convert to fraction form
    31.85/47.79 = 13.83/x
  3. Step 3: Cross multiply
    31.85x = 47.79 × 13.83
  4. Step 4: Simplify right side
    31.85x = 660.89
  5. Step 5: Solve for x
    x = 660.89/31.85
  6. Step 6: Final answer
    x = 20.75

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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.