Finding the Fourth Proportional to 21,577.38, 29,779.38 and 12,147.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,577.38 : 29,779.38 = 12,147.72 : x
2. Step 2: Convert to fraction form
   21,577.38/29,779.38 = 12,147.72/x
3. Step 3: Cross multiply
   21,577.38x = 29,779.38 × 12,147.72
4. Step 4: Simplify right side
   21,577.38x = 361,751,570.01
5. Step 5: Solve for x
   x = 361,751,570.01/21,577.38
6. Step 6: Final answer
   x = 16,765.31