Finding the Fourth Proportional to 1,082.06, 1,493.27 and 639.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,082.06 : 1,493.27 = 639.80 : x
2. Step 2: Convert to fraction form
   1,082.06/1,493.27 = 639.80/x
3. Step 3: Cross multiply
   1,082.06x = 1,493.27 × 639.80
4. Step 4: Simplify right side
   1,082.06x = 955,388.28
5. Step 5: Solve for x
   x = 955,388.28/1,082.06
6. Step 6: Final answer
   x = 882.94