Finding the Fourth Proportional to 99,665.39, 137,571.56 and 59,391.78

Step by Step Solution

1. Step 1: Write the proportion equation
   99,665.39 : 137,571.56 = 59,391.78 : x
2. Step 2: Convert to fraction form
   99,665.39/137,571.56 = 59,391.78/x
3. Step 3: Cross multiply
   99,665.39x = 137,571.56 × 59,391.78
4. Step 4: Simplify right side
   99,665.39x = 8,170,619,528.82
5. Step 5: Solve for x
   x = 8,170,619,528.82/99,665.39
6. Step 6: Final answer
   x = 81,980.51