Finding the Fourth Proportional to 5,911.89, 8,815.69 and 5,621.21

Step by Step Solution

1. Step 1: Write the proportion equation
   5,911.89 : 8,815.69 = 5,621.21 : x
2. Step 2: Convert to fraction form
   5,911.89/8,815.69 = 5,621.21/x
3. Step 3: Cross multiply
   5,911.89x = 8,815.69 × 5,621.21
4. Step 4: Simplify right side
   5,911.89x = 49,554,772.60
5. Step 5: Solve for x
   x = 49,554,772.60/5,911.89
6. Step 6: Final answer
   x = 8,382.22