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Finding the Fourth Proportional to 221.92, 306.24 and 128.66

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Solution

The fourth proportional to 221.92, 306.24 and 128.66 is: 177.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.92 : 306.24 = 128.66 : x
  2. Step 2: Convert to fraction form
    221.92/306.24 = 128.66/x
  3. Step 3: Cross multiply
    221.92x = 306.24 × 128.66
  4. Step 4: Simplify right side
    221.92x = 39,400.46
  5. Step 5: Solve for x
    x = 39,400.46/221.92
  6. Step 6: Final answer
    x = 177.54

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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.