Finding the Fourth Proportional to 1,399.52, 1,931.28 and 778.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.52 : 1,931.28 = 778.48 : x
2. Step 2: Convert to fraction form
   1,399.52/1,931.28 = 778.48/x
3. Step 3: Cross multiply
   1,399.52x = 1,931.28 × 778.48
4. Step 4: Simplify right side
   1,399.52x = 1,503,462.85
5. Step 5: Solve for x
   x = 1,503,462.85/1,399.52
6. Step 6: Final answer
   x = 1,074.27