Finding the Fourth Proportional to 72,981.81, 109,460.16 and 20,378.79

Step by Step Solution

1. Step 1: Write the proportion equation
   72,981.81 : 109,460.16 = 20,378.79 : x
2. Step 2: Convert to fraction form
   72,981.81/109,460.16 = 20,378.79/x
3. Step 3: Cross multiply
   72,981.81x = 109,460.16 × 20,378.79
4. Step 4: Simplify right side
   72,981.81x = 2,230,665,614.01
5. Step 5: Solve for x
   x = 2,230,665,614.01/72,981.81
6. Step 6: Final answer
   x = 30,564.68