Finding the Fourth Proportional to 1,912.16, 2,870.40 and 1,392.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,912.16 : 2,870.40 = 1,392.96 : x
2. Step 2: Convert to fraction form
   1,912.16/2,870.40 = 1,392.96/x
3. Step 3: Cross multiply
   1,912.16x = 2,870.40 × 1,392.96
4. Step 4: Simplify right side
   1,912.16x = 3,998,352.38
5. Step 5: Solve for x
   x = 3,998,352.38/1,912.16
6. Step 6: Final answer
   x = 2,091.01