Finding the Fourth Proportional to 11,185.20, 15,436.40 and 7,401.78

Step by Step Solution

1. Step 1: Write the proportion equation
   11,185.20 : 15,436.40 = 7,401.78 : x
2. Step 2: Convert to fraction form
   11,185.20/15,436.40 = 7,401.78/x
3. Step 3: Cross multiply
   11,185.20x = 15,436.40 × 7,401.78
4. Step 4: Simplify right side
   11,185.20x = 114,256,799.78
5. Step 5: Solve for x
   x = 114,256,799.78/11,185.20
6. Step 6: Final answer
   x = 10,215.00