Finding the Fourth Proportional to 82,405.89, 123,608.79 and 78,198.64

Step by Step Solution

1. Step 1: Write the proportion equation
   82,405.89 : 123,608.79 = 78,198.64 : x
2. Step 2: Convert to fraction form
   82,405.89/123,608.79 = 78,198.64/x
3. Step 3: Cross multiply
   82,405.89x = 123,608.79 × 78,198.64
4. Step 4: Simplify right side
   82,405.89x = 9,666,038,961.02
5. Step 5: Solve for x
   x = 9,666,038,961.02/82,405.89
6. Step 6: Final answer
   x = 117,297.91