Finding the Fourth Proportional to 11,781.64, 17,674.89 and 3,990.25

Step by Step Solution

1. Step 1: Write the proportion equation
   11,781.64 : 17,674.89 = 3,990.25 : x
2. Step 2: Convert to fraction form
   11,781.64/17,674.89 = 3,990.25/x
3. Step 3: Cross multiply
   11,781.64x = 17,674.89 × 3,990.25
4. Step 4: Simplify right side
   11,781.64x = 70,527,229.82
5. Step 5: Solve for x
   x = 70,527,229.82/11,781.64
6. Step 6: Final answer
   x = 5,986.20