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Finding the Fourth Proportional to 120.78, 166.62 and 74.13

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Solution

The fourth proportional to 120.78, 166.62 and 74.13 is: 102.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.78 : 166.62 = 74.13 : x
  2. Step 2: Convert to fraction form
    120.78/166.62 = 74.13/x
  3. Step 3: Cross multiply
    120.78x = 166.62 × 74.13
  4. Step 4: Simplify right side
    120.78x = 12,351.54
  5. Step 5: Solve for x
    x = 12,351.54/120.78
  6. Step 6: Final answer
    x = 102.26

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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.