Finding the Fourth Proportional to 1,393.68, 1,923.20 and 772.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,393.68 : 1,923.20 = 772.72 : x
2. Step 2: Convert to fraction form
   1,393.68/1,923.20 = 772.72/x
3. Step 3: Cross multiply
   1,393.68x = 1,923.20 × 772.72
4. Step 4: Simplify right side
   1,393.68x = 1,486,095.10
5. Step 5: Solve for x
   x = 1,486,095.10/1,393.68
6. Step 6: Final answer
   x = 1,066.31