Finding the Fourth Proportional to 91,931.81, 138,014.37 and 78,168.29

Step by Step Solution

1. Step 1: Write the proportion equation
   91,931.81 : 138,014.37 = 78,168.29 : x
2. Step 2: Convert to fraction form
   91,931.81/138,014.37 = 78,168.29/x
3. Step 3: Cross multiply
   91,931.81x = 138,014.37 × 78,168.29
4. Step 4: Simplify right side
   91,931.81x = 10,788,346,608.26
5. Step 5: Solve for x
   x = 10,788,346,608.26/91,931.81
6. Step 6: Final answer
   x = 117,351.62