Finding the Fourth Proportional to 20,855.58, 31,287.98 and 11,490.78

Step by Step Solution

1. Step 1: Write the proportion equation
   20,855.58 : 31,287.98 = 11,490.78 : x
2. Step 2: Convert to fraction form
   20,855.58/31,287.98 = 11,490.78/x
3. Step 3: Cross multiply
   20,855.58x = 31,287.98 × 11,490.78
4. Step 4: Simplify right side
   20,855.58x = 359,523,323.55
5. Step 5: Solve for x
   x = 359,523,323.55/20,855.58
6. Step 6: Final answer
   x = 17,238.71