Finding the Fourth Proportional to 85,856.72, 128,153.45 and 79,840.04

Step by Step Solution

1. Step 1: Write the proportion equation
   85,856.72 : 128,153.45 = 79,840.04 : x
2. Step 2: Convert to fraction form
   85,856.72/128,153.45 = 79,840.04/x
3. Step 3: Cross multiply
   85,856.72x = 128,153.45 × 79,840.04
4. Step 4: Simplify right side
   85,856.72x = 10,231,776,132.97
5. Step 5: Solve for x
   x = 10,231,776,132.97/85,856.72
6. Step 6: Final answer
   x = 119,172.70