Finding the Fourth Proportional to 1,082.10, 1,493.30 and 640.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,082.10 : 1,493.30 = 640.21 : x
2. Step 2: Convert to fraction form
   1,082.10/1,493.30 = 640.21/x
3. Step 3: Cross multiply
   1,082.10x = 1,493.30 × 640.21
4. Step 4: Simplify right side
   1,082.10x = 956,025.59
5. Step 5: Solve for x
   x = 956,025.59/1,082.10
6. Step 6: Final answer
   x = 883.49