Finding the Fourth Proportional to 128,734.50, 177,664.55 and 72,156.81

Step by Step Solution

1. Step 1: Write the proportion equation
   128,734.50 : 177,664.55 = 72,156.81 : x
2. Step 2: Convert to fraction form
   128,734.50/177,664.55 = 72,156.81/x
3. Step 3: Cross multiply
   128,734.50x = 177,664.55 × 72,156.81
4. Step 4: Simplify right side
   128,734.50x = 12,819,706,817.30
5. Step 5: Solve for x
   x = 12,819,706,817.30/128,734.50
6. Step 6: Final answer
   x = 99,582.53