Finding the Fourth Proportional to 1,129.82, 1,558.87 and 687.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,129.82 : 1,558.87 = 687.69 : x
2. Step 2: Convert to fraction form
   1,129.82/1,558.87 = 687.69/x
3. Step 3: Cross multiply
   1,129.82x = 1,558.87 × 687.69
4. Step 4: Simplify right side
   1,129.82x = 1,072,017.59
5. Step 5: Solve for x
   x = 1,072,017.59/1,129.82
6. Step 6: Final answer
   x = 948.84