Finding the Fourth Proportional to 1,131.29, 1,561.11 and 689.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.29 : 1,561.11 = 689.10 : x
2. Step 2: Convert to fraction form
   1,131.29/1,561.11 = 689.10/x
3. Step 3: Cross multiply
   1,131.29x = 1,561.11 × 689.10
4. Step 4: Simplify right side
   1,131.29x = 1,075,760.90
5. Step 5: Solve for x
   x = 1,075,760.90/1,131.29
6. Step 6: Final answer
   x = 950.92