Finding the Fourth Proportional to 1,392.39, 1,921.52 and 762.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.39 : 1,921.52 = 762.90 : x
2. Step 2: Convert to fraction form
   1,392.39/1,921.52 = 762.90/x
3. Step 3: Cross multiply
   1,392.39x = 1,921.52 × 762.90
4. Step 4: Simplify right side
   1,392.39x = 1,465,923.79
5. Step 5: Solve for x
   x = 1,465,923.79/1,392.39
6. Step 6: Final answer
   x = 1,052.81