Finding the Fourth Proportional to 19,981.89, 29,991.33 and 10,128.11

Step by Step Solution

1. Step 1: Write the proportion equation
   19,981.89 : 29,991.33 = 10,128.11 : x
2. Step 2: Convert to fraction form
   19,981.89/29,991.33 = 10,128.11/x
3. Step 3: Cross multiply
   19,981.89x = 29,991.33 × 10,128.11
4. Step 4: Simplify right side
   19,981.89x = 303,755,339.33
5. Step 5: Solve for x
   x = 303,755,339.33/19,981.89
6. Step 6: Final answer
   x = 15,201.53