Finding the Fourth Proportional to 21,159.38, 29,199.72 and 12,206.78

Step by Step Solution

1. Step 1: Write the proportion equation
   21,159.38 : 29,199.72 = 12,206.78 : x
2. Step 2: Convert to fraction form
   21,159.38/29,199.72 = 12,206.78/x
3. Step 3: Cross multiply
   21,159.38x = 29,199.72 × 12,206.78
4. Step 4: Simplify right side
   21,159.38x = 356,434,558.10
5. Step 5: Solve for x
   x = 356,434,558.10/21,159.38
6. Step 6: Final answer
   x = 16,845.23