Finding the Fourth Proportional to 1,191.57, 1,644.33 and 667.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.57 : 1,644.33 = 667.63 : x
2. Step 2: Convert to fraction form
   1,191.57/1,644.33 = 667.63/x
3. Step 3: Cross multiply
   1,191.57x = 1,644.33 × 667.63
4. Step 4: Simplify right side
   1,191.57x = 1,097,804.04
5. Step 5: Solve for x
   x = 1,097,804.04/1,191.57
6. Step 6: Final answer
   x = 921.31