Finding the Fourth Proportional to 1,191.82, 1,644.72 and 667.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.82 : 1,644.72 = 667.90 : x
2. Step 2: Convert to fraction form
   1,191.82/1,644.72 = 667.90/x
3. Step 3: Cross multiply
   1,191.82x = 1,644.72 × 667.90
4. Step 4: Simplify right side
   1,191.82x = 1,098,508.49
5. Step 5: Solve for x
   x = 1,098,508.49/1,191.82
6. Step 6: Final answer
   x = 921.71