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Finding the Fourth Proportional to 221.81, 306.11 and 138.92

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Solution

The fourth proportional to 221.81, 306.11 and 138.92 is: 191.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.81 : 306.11 = 138.92 : x
  2. Step 2: Convert to fraction form
    221.81/306.11 = 138.92/x
  3. Step 3: Cross multiply
    221.81x = 306.11 × 138.92
  4. Step 4: Simplify right side
    221.81x = 42,523.62
  5. Step 5: Solve for x
    x = 42,523.62/221.81
  6. Step 6: Final answer
    x = 191.72

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.