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Finding the Fourth Proportional to 221.70, 306.18 and 138.87

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Solution

The fourth proportional to 221.70, 306.18 and 138.87 is: 191.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.70 : 306.18 = 138.87 : x
  2. Step 2: Convert to fraction form
    221.70/306.18 = 138.87/x
  3. Step 3: Cross multiply
    221.70x = 306.18 × 138.87
  4. Step 4: Simplify right side
    221.70x = 42,519.22
  5. Step 5: Solve for x
    x = 42,519.22/221.70
  6. Step 6: Final answer
    x = 191.79

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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.