Finding the Fourth Proportional to 10,505.16, 15,744.78 and 5,821.20

Step by Step Solution

1. Step 1: Write the proportion equation
   10,505.16 : 15,744.78 = 5,821.20 : x
2. Step 2: Convert to fraction form
   10,505.16/15,744.78 = 5,821.20/x
3. Step 3: Cross multiply
   10,505.16x = 15,744.78 × 5,821.20
4. Step 4: Simplify right side
   10,505.16x = 91,653,513.34
5. Step 5: Solve for x
   x = 91,653,513.34/10,505.16
6. Step 6: Final answer
   x = 8,724.62