Finding the Fourth Proportional to 90,861.72, 136,898.28 and 83,688.36

Step by Step Solution

1. Step 1: Write the proportion equation
   90,861.72 : 136,898.28 = 83,688.36 : x
2. Step 2: Convert to fraction form
   90,861.72/136,898.28 = 83,688.36/x
3. Step 3: Cross multiply
   90,861.72x = 136,898.28 × 83,688.36
4. Step 4: Simplify right side
   90,861.72x = 11,456,792,540.02
5. Step 5: Solve for x
   x = 11,456,792,540.02/90,861.72
6. Step 6: Final answer
   x = 126,090.42