Finding the Fourth Proportional to 1,401.60, 1,934.08 and 780.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.60 : 1,934.08 = 780.48 : x
2. Step 2: Convert to fraction form
   1,401.60/1,934.08 = 780.48/x
3. Step 3: Cross multiply
   1,401.60x = 1,934.08 × 780.48
4. Step 4: Simplify right side
   1,401.60x = 1,509,510.76
5. Step 5: Solve for x
   x = 1,509,510.76/1,401.60
6. Step 6: Final answer
   x = 1,076.99