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Finding the Fourth Proportional to 221.60, 305.82 and 128.39

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Solution

The fourth proportional to 221.60, 305.82 and 128.39 is: 177.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.60 : 305.82 = 128.39 : x
  2. Step 2: Convert to fraction form
    221.60/305.82 = 128.39/x
  3. Step 3: Cross multiply
    221.60x = 305.82 × 128.39
  4. Step 4: Simplify right side
    221.60x = 39,262.34
  5. Step 5: Solve for x
    x = 39,262.34/221.60
  6. Step 6: Final answer
    x = 177.17

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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.