Finding the Fourth Proportional to 5,185.89, 7,778.93 and 1,290.31

Step by Step Solution

1. Step 1: Write the proportion equation
   5,185.89 : 7,778.93 = 1,290.31 : x
2. Step 2: Convert to fraction form
   5,185.89/7,778.93 = 1,290.31/x
3. Step 3: Cross multiply
   5,185.89x = 7,778.93 × 1,290.31
4. Step 4: Simplify right side
   5,185.89x = 10,037,205.27
5. Step 5: Solve for x
   x = 10,037,205.27/5,185.89
6. Step 6: Final answer
   x = 1,935.48