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Finding the Fourth Proportional to 120.61, 166.38 and 76.90

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Solution

The fourth proportional to 120.61, 166.38 and 76.90 is: 106.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.61 : 166.38 = 76.90 : x
  2. Step 2: Convert to fraction form
    120.61/166.38 = 76.90/x
  3. Step 3: Cross multiply
    120.61x = 166.38 × 76.90
  4. Step 4: Simplify right side
    120.61x = 12,794.62
  5. Step 5: Solve for x
    x = 12,794.62/120.61
  6. Step 6: Final answer
    x = 106.08

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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.