Finding the Fourth Proportional to 3,456.76, 5,185.90 and 991.39

Step by Step Solution

1. Step 1: Write the proportion equation
   3,456.76 : 5,185.90 = 991.39 : x
2. Step 2: Convert to fraction form
   3,456.76/5,185.90 = 991.39/x
3. Step 3: Cross multiply
   3,456.76x = 5,185.90 × 991.39
4. Step 4: Simplify right side
   3,456.76x = 5,141,224.09
5. Step 5: Solve for x
   x = 5,141,224.09/3,456.76
6. Step 6: Final answer
   x = 1,487.30