Finding the Fourth Proportional to 1,138.89, 1,571.57 and 696.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,138.89 : 1,571.57 = 696.72 : x
2. Step 2: Convert to fraction form
   1,138.89/1,571.57 = 696.72/x
3. Step 3: Cross multiply
   1,138.89x = 1,571.57 × 696.72
4. Step 4: Simplify right side
   1,138.89x = 1,094,940.77
5. Step 5: Solve for x
   x = 1,094,940.77/1,138.89
6. Step 6: Final answer
   x = 961.41