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Finding the Fourth Proportional to 19.91, 29.81 and 12.67

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Solution

The fourth proportional to 19.91, 29.81 and 12.67 is: 18.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.91 : 29.81 = 12.67 : x
  2. Step 2: Convert to fraction form
    19.91/29.81 = 12.67/x
  3. Step 3: Cross multiply
    19.91x = 29.81 × 12.67
  4. Step 4: Simplify right side
    19.91x = 377.48
  5. Step 5: Solve for x
    x = 377.48/19.91
  6. Step 6: Final answer
    x = 18.96

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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.