Finding the Fourth Proportional to 72,039.09, 99,419.58 and 40,212.78

Step by Step Solution

1. Step 1: Write the proportion equation
   72,039.09 : 99,419.58 = 40,212.78 : x
2. Step 2: Convert to fraction form
   72,039.09/99,419.58 = 40,212.78/x
3. Step 3: Cross multiply
   72,039.09x = 99,419.58 × 40,212.78
4. Step 4: Simplify right side
   72,039.09x = 3,997,937,698.23
5. Step 5: Solve for x
   x = 3,997,937,698.23/72,039.09
6. Step 6: Final answer
   x = 55,496.78