Finding the Fourth Proportional to 123,611.71, 170,612 and 72,640.81

Step by Step Solution

1. Step 1: Write the proportion equation
   123,611.71 : 170,612 = 72,640.81 : x
2. Step 2: Convert to fraction form
   123,611.71/170,612 = 72,640.81/x
3. Step 3: Cross multiply
   123,611.71x = 170,612 × 72,640.81
4. Step 4: Simplify right side
   123,611.71x = 12,393,393,875.72
5. Step 5: Solve for x
   x = 12,393,393,875.72/123,611.71
6. Step 6: Final answer
   x = 100,260.68