Finding the Fourth Proportional to 21,172.78, 31,756.72 and 5,591.62

Step by Step Solution

1. Step 1: Write the proportion equation
   21,172.78 : 31,756.72 = 5,591.62 : x
2. Step 2: Convert to fraction form
   21,172.78/31,756.72 = 5,591.62/x
3. Step 3: Cross multiply
   21,172.78x = 31,756.72 × 5,591.62
4. Step 4: Simplify right side
   21,172.78x = 177,571,510.69
5. Step 5: Solve for x
   x = 177,571,510.69/21,172.78
6. Step 6: Final answer
   x = 8,386.78