Finding the Fourth Proportional to 21,851.21, 30,155.58 and 12,898.71

Step by Step Solution

1. Step 1: Write the proportion equation
   21,851.21 : 30,155.58 = 12,898.71 : x
2. Step 2: Convert to fraction form
   21,851.21/30,155.58 = 12,898.71/x
3. Step 3: Cross multiply
   21,851.21x = 30,155.58 × 12,898.71
4. Step 4: Simplify right side
   21,851.21x = 388,968,081.30
5. Step 5: Solve for x
   x = 388,968,081.30/21,851.21
6. Step 6: Final answer
   x = 17,800.76