Finding the Fourth Proportional to 139,131.20, 208,543.20 and 76,846.40

Step by Step Solution

1. Step 1: Write the proportion equation
   139,131.20 : 208,543.20 = 76,846.40 : x
2. Step 2: Convert to fraction form
   139,131.20/208,543.20 = 76,846.40/x
3. Step 3: Cross multiply
   139,131.20x = 208,543.20 × 76,846.40
4. Step 4: Simplify right side
   139,131.20x = 16,025,794,164.48
5. Step 5: Solve for x
   x = 16,025,794,164.48/139,131.20
6. Step 6: Final answer
   x = 115,184.76