Finding the Fourth Proportional to 21,056.22, 31,579.98 and 7,908.30

Step by Step Solution

1. Step 1: Write the proportion equation
   21,056.22 : 31,579.98 = 7,908.30 : x
2. Step 2: Convert to fraction form
   21,056.22/31,579.98 = 7,908.30/x
3. Step 3: Cross multiply
   21,056.22x = 31,579.98 × 7,908.30
4. Step 4: Simplify right side
   21,056.22x = 249,743,955.83
5. Step 5: Solve for x
   x = 249,743,955.83/21,056.22
6. Step 6: Final answer
   x = 11,860.82