Finding the Fourth Proportional to 1,131.78, 1,562.11 and 689.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.78 : 1,562.11 = 689.59 : x
2. Step 2: Convert to fraction form
   1,131.78/1,562.11 = 689.59/x
3. Step 3: Cross multiply
   1,131.78x = 1,562.11 × 689.59
4. Step 4: Simplify right side
   1,131.78x = 1,077,209.81
5. Step 5: Solve for x
   x = 1,077,209.81/1,131.78
6. Step 6: Final answer
   x = 951.78