Finding the Fourth Proportional to 1,191.34, 1,643.90 and 667.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.34 : 1,643.90 = 667.38 : x
2. Step 2: Convert to fraction form
   1,191.34/1,643.90 = 667.38/x
3. Step 3: Cross multiply
   1,191.34x = 1,643.90 × 667.38
4. Step 4: Simplify right side
   1,191.34x = 1,097,105.98
5. Step 5: Solve for x
   x = 1,097,105.98/1,191.34
6. Step 6: Final answer
   x = 920.90