Finding the Fourth Proportional to 3,456.45, 5,185.47 and 991.29

Step by Step Solution

1. Step 1: Write the proportion equation
   3,456.45 : 5,185.47 = 991.29 : x
2. Step 2: Convert to fraction form
   3,456.45/5,185.47 = 991.29/x
3. Step 3: Cross multiply
   3,456.45x = 5,185.47 × 991.29
4. Step 4: Simplify right side
   3,456.45x = 5,140,304.56
5. Step 5: Solve for x
   x = 5,140,304.56/3,456.45
6. Step 6: Final answer
   x = 1,487.16