Finding the Fourth Proportional to 21,353.02, 29,465.47 and 12,399.05

Step by Step Solution

1. Step 1: Write the proportion equation
   21,353.02 : 29,465.47 = 12,399.05 : x
2. Step 2: Convert to fraction form
   21,353.02/29,465.47 = 12,399.05/x
3. Step 3: Cross multiply
   21,353.02x = 29,465.47 × 12,399.05
4. Step 4: Simplify right side
   21,353.02x = 365,343,835.80
5. Step 5: Solve for x
   x = 365,343,835.80/21,353.02
6. Step 6: Final answer
   x = 17,109.70