Finding the Fourth Proportional to 72,720.91, 109,081.52 and 20,130.55

Step by Step Solution

1. Step 1: Write the proportion equation
   72,720.91 : 109,081.52 = 20,130.55 : x
2. Step 2: Convert to fraction form
   72,720.91/109,081.52 = 20,130.55/x
3. Step 3: Cross multiply
   72,720.91x = 109,081.52 × 20,130.55
4. Step 4: Simplify right side
   72,720.91x = 2,195,870,891.78
5. Step 5: Solve for x
   x = 2,195,870,891.78/72,720.91
6. Step 6: Final answer
   x = 30,195.87