Finding the Fourth Proportional to 1,191.89, 1,644.89 and 667.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.89 : 1,644.89 = 667.91 : x
2. Step 2: Convert to fraction form
   1,191.89/1,644.89 = 667.91/x
3. Step 3: Cross multiply
   1,191.89x = 1,644.89 × 667.91
4. Step 4: Simplify right side
   1,191.89x = 1,098,626.92
5. Step 5: Solve for x
   x = 1,098,626.92/1,191.89
6. Step 6: Final answer
   x = 921.76