Finding the Fourth Proportional to 1,392.53, 2,089.83 and 1,121.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.53 : 2,089.83 = 1,121.90 : x
2. Step 2: Convert to fraction form
   1,392.53/2,089.83 = 1,121.90/x
3. Step 3: Cross multiply
   1,392.53x = 2,089.83 × 1,121.90
4. Step 4: Simplify right side
   1,392.53x = 2,344,569.83
5. Step 5: Solve for x
   x = 2,344,569.83/1,392.53
6. Step 6: Final answer
   x = 1,683.68