Finding the Fourth Proportional to 139,111.68, 191,971.12 and 78,674.40

Step by Step Solution

1. Step 1: Write the proportion equation
   139,111.68 : 191,971.12 = 78,674.40 : x
2. Step 2: Convert to fraction form
   139,111.68/191,971.12 = 78,674.40/x
3. Step 3: Cross multiply
   139,111.68x = 191,971.12 × 78,674.40
4. Step 4: Simplify right side
   139,111.68x = 15,103,212,683.33
5. Step 5: Solve for x
   x = 15,103,212,683.33/139,111.68
6. Step 6: Final answer
   x = 108,568.98