Finding the Fourth Proportional to 91,458.15, 137,872.72 and 85,361.89

Step by Step Solution

1. Step 1: Write the proportion equation
   91,458.15 : 137,872.72 = 85,361.89 : x
2. Step 2: Convert to fraction form
   91,458.15/137,872.72 = 85,361.89/x
3. Step 3: Cross multiply
   91,458.15x = 137,872.72 × 85,361.89
4. Step 4: Simplify right side
   91,458.15x = 11,769,074,842.47
5. Step 5: Solve for x
   x = 11,769,074,842.47/91,458.15
6. Step 6: Final answer
   x = 128,682.63