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Finding the Fourth Proportional to 120.91, 181.55 and 115.78

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Solution

The fourth proportional to 120.91, 181.55 and 115.78 is: 173.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.91 : 181.55 = 115.78 : x
  2. Step 2: Convert to fraction form
    120.91/181.55 = 115.78/x
  3. Step 3: Cross multiply
    120.91x = 181.55 × 115.78
  4. Step 4: Simplify right side
    120.91x = 21,019.86
  5. Step 5: Solve for x
    x = 21,019.86/120.91
  6. Step 6: Final answer
    x = 173.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.