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Finding the Fourth Proportional to 221.79, 331.89 and 139.56

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Solution

The fourth proportional to 221.79, 331.89 and 139.56 is: 208.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.79 : 331.89 = 139.56 : x
  2. Step 2: Convert to fraction form
    221.79/331.89 = 139.56/x
  3. Step 3: Cross multiply
    221.79x = 331.89 × 139.56
  4. Step 4: Simplify right side
    221.79x = 46,318.57
  5. Step 5: Solve for x
    x = 46,318.57/221.79
  6. Step 6: Final answer
    x = 208.84

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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.