Finding the Fourth Proportional to 3,456.24, 5,185.23 and 991.28

Step by Step Solution

1. Step 1: Write the proportion equation
   3,456.24 : 5,185.23 = 991.28 : x
2. Step 2: Convert to fraction form
   3,456.24/5,185.23 = 991.28/x
3. Step 3: Cross multiply
   3,456.24x = 5,185.23 × 991.28
4. Step 4: Simplify right side
   3,456.24x = 5,139,988.87
5. Step 5: Solve for x
   x = 5,139,988.87/3,456.24
6. Step 6: Final answer
   x = 1,487.16