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Finding the Fourth Proportional to 120.78, 166.73 and 74.19

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Solution

The fourth proportional to 120.78, 166.73 and 74.19 is: 102.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.78 : 166.73 = 74.19 : x
  2. Step 2: Convert to fraction form
    120.78/166.73 = 74.19/x
  3. Step 3: Cross multiply
    120.78x = 166.73 × 74.19
  4. Step 4: Simplify right side
    120.78x = 12,369.70
  5. Step 5: Solve for x
    x = 12,369.70/120.78
  6. Step 6: Final answer
    x = 102.42

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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.