Finding the Fourth Proportional to 1,409.78, 1,945.50 and 780.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,409.78 : 1,945.50 = 780.35 : x
2. Step 2: Convert to fraction form
   1,409.78/1,945.50 = 780.35/x
3. Step 3: Cross multiply
   1,409.78x = 1,945.50 × 780.35
4. Step 4: Simplify right side
   1,409.78x = 1,518,163.38
5. Step 5: Solve for x
   x = 1,518,163.38/1,409.78
6. Step 6: Final answer
   x = 1,076.88