Finding the Fourth Proportional to 1,392.76, 1,921.94 and 771.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.76 : 1,921.94 = 771.72 : x
2. Step 2: Convert to fraction form
   1,392.76/1,921.94 = 771.72/x
3. Step 3: Cross multiply
   1,392.76x = 1,921.94 × 771.72
4. Step 4: Simplify right side
   1,392.76x = 1,483,199.54
5. Step 5: Solve for x
   x = 1,483,199.54/1,392.76
6. Step 6: Final answer
   x = 1,064.94