Finding the Fourth Proportional to 9,166.16, 12,617.34 and 7,911.20

Step by Step Solution

1. Step 1: Write the proportion equation
   9,166.16 : 12,617.34 = 7,911.20 : x
2. Step 2: Convert to fraction form
   9,166.16/12,617.34 = 7,911.20/x
3. Step 3: Cross multiply
   9,166.16x = 12,617.34 × 7,911.20
4. Step 4: Simplify right side
   9,166.16x = 99,818,300.21
5. Step 5: Solve for x
   x = 99,818,300.21/9,166.16
6. Step 6: Final answer
   x = 10,889.87