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Finding the Fourth Proportional to 160.78, 221.45 and 138.91

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Solution

The fourth proportional to 160.78, 221.45 and 138.91 is: 191.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    160.78 : 221.45 = 138.91 : x
  2. Step 2: Convert to fraction form
    160.78/221.45 = 138.91/x
  3. Step 3: Cross multiply
    160.78x = 221.45 × 138.91
  4. Step 4: Simplify right side
    160.78x = 30,761.62
  5. Step 5: Solve for x
    x = 30,761.62/160.78
  6. Step 6: Final answer
    x = 191.33

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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.