Finding the Fourth Proportional to 1,191.81, 1,644.71 and 660.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.81 : 1,644.71 = 660.71 : x
2. Step 2: Convert to fraction form
   1,191.81/1,644.71 = 660.71/x
3. Step 3: Cross multiply
   1,191.81x = 1,644.71 × 660.71
4. Step 4: Simplify right side
   1,191.81x = 1,086,664.82
5. Step 5: Solve for x
   x = 1,086,664.82/1,191.81
6. Step 6: Final answer
   x = 911.78