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Finding the Fourth Proportional to 120.82, 166.78 and 85.86

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Solution

The fourth proportional to 120.82, 166.78 and 85.86 is: 118.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.82 : 166.78 = 85.86 : x
  2. Step 2: Convert to fraction form
    120.82/166.78 = 85.86/x
  3. Step 3: Cross multiply
    120.82x = 166.78 × 85.86
  4. Step 4: Simplify right side
    120.82x = 14,319.73
  5. Step 5: Solve for x
    x = 14,319.73/120.82
  6. Step 6: Final answer
    x = 118.52

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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.