Finding the Fourth Proportional to 139,409.33, 192,378.59 and 78,978.74

Step by Step Solution

1. Step 1: Write the proportion equation
   139,409.33 : 192,378.59 = 78,978.74 : x
2. Step 2: Convert to fraction form
   139,409.33/192,378.59 = 78,978.74/x
3. Step 3: Cross multiply
   139,409.33x = 192,378.59 × 78,978.74
4. Step 4: Simplify right side
   139,409.33x = 15,193,817,284.39
5. Step 5: Solve for x
   x = 15,193,817,284.39/139,409.33
6. Step 6: Final answer
   x = 108,987.09