Finding the Fourth Proportional to 105,128.52, 156,925.20 and 91,186.80

Step by Step Solution

1. Step 1: Write the proportion equation
   105,128.52 : 156,925.20 = 91,186.80 : x
2. Step 2: Convert to fraction form
   105,128.52/156,925.20 = 91,186.80/x
3. Step 3: Cross multiply
   105,128.52x = 156,925.20 × 91,186.80
4. Step 4: Simplify right side
   105,128.52x = 14,309,506,827.36
5. Step 5: Solve for x
   x = 14,309,506,827.36/105,128.52
6. Step 6: Final answer
   x = 136,114.41