Finding the Fourth Proportional to 11,912.80, 17,855.82 and 5,590.78

Step by Step Solution

1. Step 1: Write the proportion equation
   11,912.80 : 17,855.82 = 5,590.78 : x
2. Step 2: Convert to fraction form
   11,912.80/17,855.82 = 5,590.78/x
3. Step 3: Cross multiply
   11,912.80x = 17,855.82 × 5,590.78
4. Step 4: Simplify right side
   11,912.80x = 99,827,961.34
5. Step 5: Solve for x
   x = 99,827,961.34/11,912.80
6. Step 6: Final answer
   x = 8,379.89