Finding the Fourth Proportional to 1,191.55, 1,644.17 and 660.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.55 : 1,644.17 = 660.35 : x
2. Step 2: Convert to fraction form
   1,191.55/1,644.17 = 660.35/x
3. Step 3: Cross multiply
   1,191.55x = 1,644.17 × 660.35
4. Step 4: Simplify right side
   1,191.55x = 1,085,727.66
5. Step 5: Solve for x
   x = 1,085,727.66/1,191.55
6. Step 6: Final answer
   x = 911.19