Finding the Fourth Proportional to 1,392.50, 1,921.57 and 825.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.50 : 1,921.57 = 825.69 : x
2. Step 2: Convert to fraction form
   1,392.50/1,921.57 = 825.69/x
3. Step 3: Cross multiply
   1,392.50x = 1,921.57 × 825.69
4. Step 4: Simplify right side
   1,392.50x = 1,586,621.13
5. Step 5: Solve for x
   x = 1,586,621.13/1,392.50
6. Step 6: Final answer
   x = 1,139.40