Finding the Fourth Proportional to 1,131.75, 1,561.91 and 666.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.75 : 1,561.91 = 666.09 : x
2. Step 2: Convert to fraction form
   1,131.75/1,561.91 = 666.09/x
3. Step 3: Cross multiply
   1,131.75x = 1,561.91 × 666.09
4. Step 4: Simplify right side
   1,131.75x = 1,040,369.30
5. Step 5: Solve for x
   x = 1,040,369.30/1,131.75
6. Step 6: Final answer
   x = 919.26