Finding the Fourth Proportional to 21,840.10, 30,139.32 and 12,887.62

Step by Step Solution

1. Step 1: Write the proportion equation
   21,840.10 : 30,139.32 = 12,887.62 : x
2. Step 2: Convert to fraction form
   21,840.10/30,139.32 = 12,887.62/x
3. Step 3: Cross multiply
   21,840.10x = 30,139.32 × 12,887.62
4. Step 4: Simplify right side
   21,840.10x = 388,424,103.22
5. Step 5: Solve for x
   x = 388,424,103.22/21,840.10
6. Step 6: Final answer
   x = 17,784.90