Finding the Fourth Proportional to 11,891.10, 16,404.57 and 7,172.67

Step by Step Solution

1. Step 1: Write the proportion equation
   11,891.10 : 16,404.57 = 7,172.67 : x
2. Step 2: Convert to fraction form
   11,891.10/16,404.57 = 7,172.67/x
3. Step 3: Cross multiply
   11,891.10x = 16,404.57 × 7,172.67
4. Step 4: Simplify right side
   11,891.10x = 117,664,567.10
5. Step 5: Solve for x
   x = 117,664,567.10/11,891.10
6. Step 6: Final answer
   x = 9,895.18