Finding the Fourth Proportional to 11,435.76, 15,780.24 and 6,399.72

Step by Step Solution

1. Step 1: Write the proportion equation
   11,435.76 : 15,780.24 = 6,399.72 : x
2. Step 2: Convert to fraction form
   11,435.76/15,780.24 = 6,399.72/x
3. Step 3: Cross multiply
   11,435.76x = 15,780.24 × 6,399.72
4. Step 4: Simplify right side
   11,435.76x = 100,989,117.53
5. Step 5: Solve for x
   x = 100,989,117.53/11,435.76
6. Step 6: Final answer
   x = 8,830.99