Finding the Fourth Proportional to 71,812.46, 99,099.50 and 39,980.72

Step by Step Solution

1. Step 1: Write the proportion equation
   71,812.46 : 99,099.50 = 39,980.72 : x
2. Step 2: Convert to fraction form
   71,812.46/99,099.50 = 39,980.72/x
3. Step 3: Cross multiply
   71,812.46x = 99,099.50 × 39,980.72
4. Step 4: Simplify right side
   71,812.46x = 3,962,069,361.64
5. Step 5: Solve for x
   x = 3,962,069,361.64/71,812.46
6. Step 6: Final answer
   x = 55,172.45