Finding the Fourth Proportional to 1,191.74, 1,644.56 and 667.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.74 : 1,644.56 = 667.77 : x
2. Step 2: Convert to fraction form
   1,191.74/1,644.56 = 667.77/x
3. Step 3: Cross multiply
   1,191.74x = 1,644.56 × 667.77
4. Step 4: Simplify right side
   1,191.74x = 1,098,187.83
5. Step 5: Solve for x
   x = 1,098,187.83/1,191.74
6. Step 6: Final answer
   x = 921.50