Finding the Fourth Proportional to 9,145.31, 12,619.90 and 5,166.18

Step by Step Solution

1. Step 1: Write the proportion equation
   9,145.31 : 12,619.90 = 5,166.18 : x
2. Step 2: Convert to fraction form
   9,145.31/12,619.90 = 5,166.18/x
3. Step 3: Cross multiply
   9,145.31x = 12,619.90 × 5,166.18
4. Step 4: Simplify right side
   9,145.31x = 65,196,681.44
5. Step 5: Solve for x
   x = 65,196,681.44/9,145.31
6. Step 6: Final answer
   x = 7,128.98