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Finding the Fourth Proportional to 120.85, 166.73 and 77.21

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Solution

The fourth proportional to 120.85, 166.73 and 77.21 is: 106.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.85 : 166.73 = 77.21 : x
  2. Step 2: Convert to fraction form
    120.85/166.73 = 77.21/x
  3. Step 3: Cross multiply
    120.85x = 166.73 × 77.21
  4. Step 4: Simplify right side
    120.85x = 12,873.83
  5. Step 5: Solve for x
    x = 12,873.83/120.85
  6. Step 6: Final answer
    x = 106.53

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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.