Finding the Fourth Proportional to 21,196.89, 31,791.69 and 7,686.70

Step by Step Solution

1. Step 1: Write the proportion equation
   21,196.89 : 31,791.69 = 7,686.70 : x
2. Step 2: Convert to fraction form
   21,196.89/31,791.69 = 7,686.70/x
3. Step 3: Cross multiply
   21,196.89x = 31,791.69 × 7,686.70
4. Step 4: Simplify right side
   21,196.89x = 244,373,104.04
5. Step 5: Solve for x
   x = 244,373,104.04/21,196.89
6. Step 6: Final answer
   x = 11,528.72