Finding the Fourth Proportional to 10,999.57, 15,175.42 and 7,224.78

Step by Step Solution

1. Step 1: Write the proportion equation
   10,999.57 : 15,175.42 = 7,224.78 : x
2. Step 2: Convert to fraction form
   10,999.57/15,175.42 = 7,224.78/x
3. Step 3: Cross multiply
   10,999.57x = 15,175.42 × 7,224.78
4. Step 4: Simplify right side
   10,999.57x = 109,639,070.91
5. Step 5: Solve for x
   x = 109,639,070.91/10,999.57
6. Step 6: Final answer
   x = 9,967.58