Finding the Fourth Proportional to 100,868.69, 139,206.20 and 72,191.05

Step by Step Solution

1. Step 1: Write the proportion equation
   100,868.69 : 139,206.20 = 72,191.05 : x
2. Step 2: Convert to fraction form
   100,868.69/139,206.20 = 72,191.05/x
3. Step 3: Cross multiply
   100,868.69x = 139,206.20 × 72,191.05
4. Step 4: Simplify right side
   100,868.69x = 10,049,441,035.54
5. Step 5: Solve for x
   x = 10,049,441,035.54/100,868.69
6. Step 6: Final answer
   x = 99,628.94