Finding the Fourth Proportional to 1,396.72, 2,078.11 and 1,391.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,396.72 : 2,078.11 = 1,391.93 : x
2. Step 2: Convert to fraction form
   1,396.72/2,078.11 = 1,391.93/x
3. Step 3: Cross multiply
   1,396.72x = 2,078.11 × 1,391.93
4. Step 4: Simplify right side
   1,396.72x = 2,892,586.65
5. Step 5: Solve for x
   x = 2,892,586.65/1,396.72
6. Step 6: Final answer
   x = 2,070.99