Finding the Fourth Proportional to 9,146.63, 12,621.33 and 5,166.90

Step by Step Solution

1. Step 1: Write the proportion equation
   9,146.63 : 12,621.33 = 5,166.90 : x
2. Step 2: Convert to fraction form
   9,146.63/12,621.33 = 5,166.90/x
3. Step 3: Cross multiply
   9,146.63x = 12,621.33 × 5,166.90
4. Step 4: Simplify right side
   9,146.63x = 65,213,149.98
5. Step 5: Solve for x
   x = 65,213,149.98/9,146.63
6. Step 6: Final answer
   x = 7,129.75