Finding the Fourth Proportional to 105,142.29, 144,728.06 and 91,689.81

Step by Step Solution

1. Step 1: Write the proportion equation
   105,142.29 : 144,728.06 = 91,689.81 : x
2. Step 2: Convert to fraction form
   105,142.29/144,728.06 = 91,689.81/x
3. Step 3: Cross multiply
   105,142.29x = 144,728.06 × 91,689.81
4. Step 4: Simplify right side
   105,142.29x = 13,270,088,323.07
5. Step 5: Solve for x
   x = 13,270,088,323.07/105,142.29
6. Step 6: Final answer
   x = 126,210.76