Finding the Fourth Proportional to 21,111.72, 29,133.18 and 12,159.48

Step by Step Solution

1. Step 1: Write the proportion equation
   21,111.72 : 29,133.18 = 12,159.48 : x
2. Step 2: Convert to fraction form
   21,111.72/29,133.18 = 12,159.48/x
3. Step 3: Cross multiply
   21,111.72x = 29,133.18 × 12,159.48
4. Step 4: Simplify right side
   21,111.72x = 354,244,319.55
5. Step 5: Solve for x
   x = 354,244,319.55/21,111.72
6. Step 6: Final answer
   x = 16,779.51