Finding the Fourth Proportional to 91,557.10, 136,956.50 and 85,958.38

Step by Step Solution

1. Step 1: Write the proportion equation
   91,557.10 : 136,956.50 = 85,958.38 : x
2. Step 2: Convert to fraction form
   91,557.10/136,956.50 = 85,958.38/x
3. Step 3: Cross multiply
   91,557.10x = 136,956.50 × 85,958.38
4. Step 4: Simplify right side
   91,557.10x = 11,772,557,755.90
5. Step 5: Solve for x
   x = 11,772,557,755.90/91,557.10
6. Step 6: Final answer
   x = 128,581.60