Finding the Fourth Proportional to 91,916.31, 137,991.12 and 78,152.79

Step by Step Solution

1. Step 1: Write the proportion equation
   91,916.31 : 137,991.12 = 78,152.79 : x
2. Step 2: Convert to fraction form
   91,916.31/137,991.12 = 78,152.79/x
3. Step 3: Cross multiply
   91,916.31x = 137,991.12 × 78,152.79
4. Step 4: Simplify right side
   91,916.31x = 10,784,391,023.22
5. Step 5: Solve for x
   x = 10,784,391,023.22/91,916.31
6. Step 6: Final answer
   x = 117,328.37