Finding the Fourth Proportional to 21,851.50, 30,155.10 and 11,915.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,851.50 : 30,155.10 = 11,915.50 : x
2. Step 2: Convert to fraction form
   21,851.50/30,155.10 = 11,915.50/x
3. Step 3: Cross multiply
   21,851.50x = 30,155.10 × 11,915.50
4. Step 4: Simplify right side
   21,851.50x = 359,313,094.05
5. Step 5: Solve for x
   x = 359,313,094.05/21,851.50
6. Step 6: Final answer
   x = 16,443.41