Finding the Fourth Proportional to 1,100.80, 1,651.92 and 639.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,100.80 : 1,651.92 = 639.52 : x
2. Step 2: Convert to fraction form
   1,100.80/1,651.92 = 639.52/x
3. Step 3: Cross multiply
   1,100.80x = 1,651.92 × 639.52
4. Step 4: Simplify right side
   1,100.80x = 1,056,435.88
5. Step 5: Solve for x
   x = 1,056,435.88/1,100.80
6. Step 6: Final answer
   x = 959.70