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Finding the Fourth Proportional to 221.98, 306.33 and 128.70

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Solution

The fourth proportional to 221.98, 306.33 and 128.70 is: 177.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.98 : 306.33 = 128.70 : x
  2. Step 2: Convert to fraction form
    221.98/306.33 = 128.70/x
  3. Step 3: Cross multiply
    221.98x = 306.33 × 128.70
  4. Step 4: Simplify right side
    221.98x = 39,424.03
  5. Step 5: Solve for x
    x = 39,424.03/221.98
  6. Step 6: Final answer
    x = 177.61

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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.