Finding the Fourth Proportional to 1,191.87, 1,644.81 and 667.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.87 : 1,644.81 = 667.89 : x
2. Step 2: Convert to fraction form
   1,191.87/1,644.81 = 667.89/x
3. Step 3: Cross multiply
   1,191.87x = 1,644.81 × 667.89
4. Step 4: Simplify right side
   1,191.87x = 1,098,552.15
5. Step 5: Solve for x
   x = 1,098,552.15/1,191.87
6. Step 6: Final answer
   x = 921.70