Finding the Fourth Proportional to 21,991.02, 30,340.05 and 12,429.78

Step by Step Solution

1. Step 1: Write the proportion equation
   21,991.02 : 30,340.05 = 12,429.78 : x
2. Step 2: Convert to fraction form
   21,991.02/30,340.05 = 12,429.78/x
3. Step 3: Cross multiply
   21,991.02x = 30,340.05 × 12,429.78
4. Step 4: Simplify right side
   21,991.02x = 377,120,146.69
5. Step 5: Solve for x
   x = 377,120,146.69/21,991.02
6. Step 6: Final answer
   x = 17,148.82