Finding the Fourth Proportional to 1,191.31, 1,643.94 and 660.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.31 : 1,643.94 = 660.18 : x
2. Step 2: Convert to fraction form
   1,191.31/1,643.94 = 660.18/x
3. Step 3: Cross multiply
   1,191.31x = 1,643.94 × 660.18
4. Step 4: Simplify right side
   1,191.31x = 1,085,296.31
5. Step 5: Solve for x
   x = 1,085,296.31/1,191.31
6. Step 6: Final answer
   x = 911.01