Finding the Fourth Proportional to 21,185.42, 31,768.26 and 7,857.88

Step by Step Solution

1. Step 1: Write the proportion equation
   21,185.42 : 31,768.26 = 7,857.88 : x
2. Step 2: Convert to fraction form
   21,185.42/31,768.26 = 7,857.88/x
3. Step 3: Cross multiply
   21,185.42x = 31,768.26 × 7,857.88
4. Step 4: Simplify right side
   21,185.42x = 249,631,174.89
5. Step 5: Solve for x
   x = 249,631,174.89/21,185.42
6. Step 6: Final answer
   x = 11,783.16