Finding the Fourth Proportional to 1,131.57, 1,561.71 and 689.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.57 : 1,561.71 = 689.54 : x
2. Step 2: Convert to fraction form
   1,131.57/1,561.71 = 689.54/x
3. Step 3: Cross multiply
   1,131.57x = 1,561.71 × 689.54
4. Step 4: Simplify right side
   1,131.57x = 1,076,850.26
5. Step 5: Solve for x
   x = 1,076,850.26/1,131.57
6. Step 6: Final answer
   x = 951.64