Finding the Fourth Proportional to 10,099.09, 15,151.72 and 5,172.21

Step by Step Solution

1. Step 1: Write the proportion equation
   10,099.09 : 15,151.72 = 5,172.21 : x
2. Step 2: Convert to fraction form
   10,099.09/15,151.72 = 5,172.21/x
3. Step 3: Cross multiply
   10,099.09x = 15,151.72 × 5,172.21
4. Step 4: Simplify right side
   10,099.09x = 78,367,851.84
5. Step 5: Solve for x
   x = 78,367,851.84/10,099.09
6. Step 6: Final answer
   x = 7,759.90