Finding the Fourth Proportional to 2,778.72, 4,168.42 and 931.16

Step by Step Solution

1. Step 1: Write the proportion equation
   2,778.72 : 4,168.42 = 931.16 : x
2. Step 2: Convert to fraction form
   2,778.72/4,168.42 = 931.16/x
3. Step 3: Cross multiply
   2,778.72x = 4,168.42 × 931.16
4. Step 4: Simplify right side
   2,778.72x = 3,881,465.97
5. Step 5: Solve for x
   x = 3,881,465.97/2,778.72
6. Step 6: Final answer
   x = 1,396.85