Finding the Fourth Proportional to 142,640.89, 196,846.85 and 78,109.09

Step by Step Solution

1. Step 1: Write the proportion equation
   142,640.89 : 196,846.85 = 78,109.09 : x
2. Step 2: Convert to fraction form
   142,640.89/196,846.85 = 78,109.09/x
3. Step 3: Cross multiply
   142,640.89x = 196,846.85 × 78,109.09
4. Step 4: Simplify right side
   142,640.89x = 15,375,528,322.87
5. Step 5: Solve for x
   x = 15,375,528,322.87/142,640.89
6. Step 6: Final answer
   x = 107,791.87