Finding the Fourth Proportional to 1,392.25, 1,921.31 and 771.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.25 : 1,921.31 = 771.25 : x
2. Step 2: Convert to fraction form
   1,392.25/1,921.31 = 771.25/x
3. Step 3: Cross multiply
   1,392.25x = 1,921.31 × 771.25
4. Step 4: Simplify right side
   1,392.25x = 1,481,810.34
5. Step 5: Solve for x
   x = 1,481,810.34/1,392.25
6. Step 6: Final answer
   x = 1,064.33