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Finding the Fourth Proportional to 221.15, 331.79 and 129.65

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Solution

The fourth proportional to 221.15, 331.79 and 129.65 is: 194.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.15 : 331.79 = 129.65 : x
  2. Step 2: Convert to fraction form
    221.15/331.79 = 129.65/x
  3. Step 3: Cross multiply
    221.15x = 331.79 × 129.65
  4. Step 4: Simplify right side
    221.15x = 43,015.93
  5. Step 5: Solve for x
    x = 43,015.93/221.15
  6. Step 6: Final answer
    x = 194.51

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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.