Finding the Fourth Proportional to 123,424.18, 170,331.57 and 72,439.12

Step by Step Solution

1. Step 1: Write the proportion equation
   123,424.18 : 170,331.57 = 72,439.12 : x
2. Step 2: Convert to fraction form
   123,424.18/170,331.57 = 72,439.12/x
3. Step 3: Cross multiply
   123,424.18x = 170,331.57 × 72,439.12
4. Step 4: Simplify right side
   123,424.18x = 12,338,669,039.02
5. Step 5: Solve for x
   x = 12,338,669,039.02/123,424.18
6. Step 6: Final answer
   x = 99,969.63