Finding the Fourth Proportional to 139,930.72, 210,143.94 and 128,811.04

Step by Step Solution

1. Step 1: Write the proportion equation
   139,930.72 : 210,143.94 = 128,811.04 : x
2. Step 2: Convert to fraction form
   139,930.72/210,143.94 = 128,811.04/x
3. Step 3: Cross multiply
   139,930.72x = 210,143.94 × 128,811.04
4. Step 4: Simplify right side
   139,930.72x = 27,068,859,461.10
5. Step 5: Solve for x
   x = 27,068,859,461.10/139,930.72
6. Step 6: Final answer
   x = 193,444.72