Finding the Fourth Proportional to 21,105.18, 31,621.41 and 13,984.98

Step by Step Solution

1. Step 1: Write the proportion equation
   21,105.18 : 31,621.41 = 13,984.98 : x
2. Step 2: Convert to fraction form
   21,105.18/31,621.41 = 13,984.98/x
3. Step 3: Cross multiply
   21,105.18x = 31,621.41 × 13,984.98
4. Step 4: Simplify right side
   21,105.18x = 442,224,786.42
5. Step 5: Solve for x
   x = 442,224,786.42/21,105.18
6. Step 6: Final answer
   x = 20,953.38