Finding the Fourth Proportional to 1,647.94, 2,472.18 and 781.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,647.94 : 2,472.18 = 781.78 : x
2. Step 2: Convert to fraction form
   1,647.94/2,472.18 = 781.78/x
3. Step 3: Cross multiply
   1,647.94x = 2,472.18 × 781.78
4. Step 4: Simplify right side
   1,647.94x = 1,932,700.88
5. Step 5: Solve for x
   x = 1,932,700.88/1,647.94
6. Step 6: Final answer
   x = 1,172.80