Finding the Fourth Proportional to 1,153.56, 1,591.92 and 687.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,153.56 : 1,591.92 = 687.81 : x
2. Step 2: Convert to fraction form
   1,153.56/1,591.92 = 687.81/x
3. Step 3: Cross multiply
   1,153.56x = 1,591.92 × 687.81
4. Step 4: Simplify right side
   1,153.56x = 1,094,938.50
5. Step 5: Solve for x
   x = 1,094,938.50/1,153.56
6. Step 6: Final answer
   x = 949.18