Finding the Fourth Proportional to 1,409.67, 1,945.20 and 780.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,409.67 : 1,945.20 = 780.21 : x
2. Step 2: Convert to fraction form
   1,409.67/1,945.20 = 780.21/x
3. Step 3: Cross multiply
   1,409.67x = 1,945.20 × 780.21
4. Step 4: Simplify right side
   1,409.67x = 1,517,664.49
5. Step 5: Solve for x
   x = 1,517,664.49/1,409.67
6. Step 6: Final answer
   x = 1,076.61