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Finding the Fourth Proportional to 120.74, 166.56 and 71.61

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Solution

The fourth proportional to 120.74, 166.56 and 71.61 is: 98.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.74 : 166.56 = 71.61 : x
  2. Step 2: Convert to fraction form
    120.74/166.56 = 71.61/x
  3. Step 3: Cross multiply
    120.74x = 166.56 × 71.61
  4. Step 4: Simplify right side
    120.74x = 11,926.94
  5. Step 5: Solve for x
    x = 11,926.94/120.74
  6. Step 6: Final answer
    x = 98.78

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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.