Finding the Fourth Proportional to 1,409.64, 1,945.17 and 780.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,409.64 : 1,945.17 = 780.15 : x
2. Step 2: Convert to fraction form
   1,409.64/1,945.17 = 780.15/x
3. Step 3: Cross multiply
   1,409.64x = 1,945.17 × 780.15
4. Step 4: Simplify right side
   1,409.64x = 1,517,534.60
5. Step 5: Solve for x
   x = 1,517,534.60/1,409.64
6. Step 6: Final answer
   x = 1,076.54