Finding the Fourth Proportional to 72,320.64, 99,732.24 and 56,399.28

Step by Step Solution

1. Step 1: Write the proportion equation
   72,320.64 : 99,732.24 = 56,399.28 : x
2. Step 2: Convert to fraction form
   72,320.64/99,732.24 = 56,399.28/x
3. Step 3: Cross multiply
   72,320.64x = 99,732.24 × 56,399.28
4. Step 4: Simplify right side
   72,320.64x = 5,624,826,528.79
5. Step 5: Solve for x
   x = 5,624,826,528.79/72,320.64
6. Step 6: Final answer
   x = 77,776.23