Finding the Fourth Proportional to 1,409.85, 1,945.61 and 780.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,409.85 : 1,945.61 = 780.36 : x
2. Step 2: Convert to fraction form
   1,409.85/1,945.61 = 780.36/x
3. Step 3: Cross multiply
   1,409.85x = 1,945.61 × 780.36
4. Step 4: Simplify right side
   1,409.85x = 1,518,272.32
5. Step 5: Solve for x
   x = 1,518,272.32/1,409.85
6. Step 6: Final answer
   x = 1,076.90