Finding the Fourth Proportional to 76,978.80, 115,506.60 and 43,724.40

Step by Step Solution

1. Step 1: Write the proportion equation
   76,978.80 : 115,506.60 = 43,724.40 : x
2. Step 2: Convert to fraction form
   76,978.80/115,506.60 = 43,724.40/x
3. Step 3: Cross multiply
   76,978.80x = 115,506.60 × 43,724.40
4. Step 4: Simplify right side
   76,978.80x = 5,050,456,781.04
5. Step 5: Solve for x
   x = 5,050,456,781.04/76,978.80
6. Step 6: Final answer
   x = 65,608.41