Finding the Fourth Proportional to 1,082.78, 1,494.30 and 640.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,082.78 : 1,494.30 = 640.58 : x
2. Step 2: Convert to fraction form
   1,082.78/1,494.30 = 640.58/x
3. Step 3: Cross multiply
   1,082.78x = 1,494.30 × 640.58
4. Step 4: Simplify right side
   1,082.78x = 957,218.69
5. Step 5: Solve for x
   x = 957,218.69/1,082.78
6. Step 6: Final answer
   x = 884.04