Finding the Fourth Proportional to 8,499.72, 12,745.20 and 3,815.72

Step by Step Solution

1. Step 1: Write the proportion equation
   8,499.72 : 12,745.20 = 3,815.72 : x
2. Step 2: Convert to fraction form
   8,499.72/12,745.20 = 3,815.72/x
3. Step 3: Cross multiply
   8,499.72x = 12,745.20 × 3,815.72
4. Step 4: Simplify right side
   8,499.72x = 48,632,055.61
5. Step 5: Solve for x
   x = 48,632,055.61/8,499.72
6. Step 6: Final answer
   x = 5,721.61