Finding the Fourth Proportional to 99,380.43, 137,189.78 and 65,406.75

Step by Step Solution

1. Step 1: Write the proportion equation
   99,380.43 : 137,189.78 = 65,406.75 : x
2. Step 2: Convert to fraction form
   99,380.43/137,189.78 = 65,406.75/x
3. Step 3: Cross multiply
   99,380.43x = 137,189.78 × 65,406.75
4. Step 4: Simplify right side
   99,380.43x = 8,973,137,315.98
5. Step 5: Solve for x
   x = 8,973,137,315.98/99,380.43
6. Step 6: Final answer
   x = 90,290.79