Finding the Fourth Proportional to 2,189.40, 3,021.86 and 1,392.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,189.40 : 3,021.86 = 1,392.57 : x
2. Step 2: Convert to fraction form
   2,189.40/3,021.86 = 1,392.57/x
3. Step 3: Cross multiply
   2,189.40x = 3,021.86 × 1,392.57
4. Step 4: Simplify right side
   2,189.40x = 4,208,151.58
5. Step 5: Solve for x
   x = 4,208,151.58/2,189.40
6. Step 6: Final answer
   x = 1,922.06