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Finding the Fourth Proportional to 221.15, 305.20 and 122.91

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Solution

The fourth proportional to 221.15, 305.20 and 122.91 is: 169.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.15 : 305.20 = 122.91 : x
  2. Step 2: Convert to fraction form
    221.15/305.20 = 122.91/x
  3. Step 3: Cross multiply
    221.15x = 305.20 × 122.91
  4. Step 4: Simplify right side
    221.15x = 37,511.14
  5. Step 5: Solve for x
    x = 37,511.14/221.15
  6. Step 6: Final answer
    x = 169.62

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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.