Finding the Fourth Proportional to 1,229.72, 1,695.60 and 809.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,229.72 : 1,695.60 = 809.93 : x
2. Step 2: Convert to fraction form
   1,229.72/1,695.60 = 809.93/x
3. Step 3: Cross multiply
   1,229.72x = 1,695.60 × 809.93
4. Step 4: Simplify right side
   1,229.72x = 1,373,321.55
5. Step 5: Solve for x
   x = 1,373,321.55/1,229.72
6. Step 6: Final answer
   x = 1,116.78