Finding the Fourth Proportional to 1,096.72, 1,643.75 and 805.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,096.72 : 1,643.75 = 805.45 : x
2. Step 2: Convert to fraction form
   1,096.72/1,643.75 = 805.45/x
3. Step 3: Cross multiply
   1,096.72x = 1,643.75 × 805.45
4. Step 4: Simplify right side
   1,096.72x = 1,323,960.57
5. Step 5: Solve for x
   x = 1,323,960.57/1,096.72
6. Step 6: Final answer
   x = 1,207.20