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Finding the Fourth Proportional to 221.33, 305.45 and 128.09

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Solution

The fourth proportional to 221.33, 305.45 and 128.09 is: 176.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.33 : 305.45 = 128.09 : x
  2. Step 2: Convert to fraction form
    221.33/305.45 = 128.09/x
  3. Step 3: Cross multiply
    221.33x = 305.45 × 128.09
  4. Step 4: Simplify right side
    221.33x = 39,122.92
  5. Step 5: Solve for x
    x = 39,122.92/221.33
  6. Step 6: Final answer
    x = 176.77

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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.