Finding the Fourth Proportional to 1,191.69, 1,644.56 and 660.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.69 : 1,644.56 = 660.60 : x
2. Step 2: Convert to fraction form
   1,191.69/1,644.56 = 660.60/x
3. Step 3: Cross multiply
   1,191.69x = 1,644.56 × 660.60
4. Step 4: Simplify right side
   1,191.69x = 1,086,393.03
5. Step 5: Solve for x
   x = 1,086,393.03/1,191.69
6. Step 6: Final answer
   x = 911.64