Finding the Fourth Proportional to 1,191.81, 1,644.87 and 667.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.81 : 1,644.87 = 667.88 : x
2. Step 2: Convert to fraction form
   1,191.81/1,644.87 = 667.88/x
3. Step 3: Cross multiply
   1,191.81x = 1,644.87 × 667.88
4. Step 4: Simplify right side
   1,191.81x = 1,098,567.55
5. Step 5: Solve for x
   x = 1,098,567.55/1,191.81
6. Step 6: Final answer
   x = 921.76