Finding the Fourth Proportional to 71,967.60, 99,315.72 and 40,138.55

Step by Step Solution

1. Step 1: Write the proportion equation
   71,967.60 : 99,315.72 = 40,138.55 : x
2. Step 2: Convert to fraction form
   71,967.60/99,315.72 = 40,138.55/x
3. Step 3: Cross multiply
   71,967.60x = 99,315.72 × 40,138.55
4. Step 4: Simplify right side
   71,967.60x = 3,986,388,496.43
5. Step 5: Solve for x
   x = 3,986,388,496.43/71,967.60
6. Step 6: Final answer
   x = 55,391.43