Finding the Fourth Proportional to 1,082.15, 1,493.15 and 640.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,082.15 : 1,493.15 = 640.18 : x
2. Step 2: Convert to fraction form
   1,082.15/1,493.15 = 640.18/x
3. Step 3: Cross multiply
   1,082.15x = 1,493.15 × 640.18
4. Step 4: Simplify right side
   1,082.15x = 955,884.77
5. Step 5: Solve for x
   x = 955,884.77/1,082.15
6. Step 6: Final answer
   x = 883.32