Finding the Fourth Proportional to 1,105.57, 1,525.68 and 639.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.57 : 1,525.68 = 639.82 : x
2. Step 2: Convert to fraction form
   1,105.57/1,525.68 = 639.82/x
3. Step 3: Cross multiply
   1,105.57x = 1,525.68 × 639.82
4. Step 4: Simplify right side
   1,105.57x = 976,160.58
5. Step 5: Solve for x
   x = 976,160.58/1,105.57
6. Step 6: Final answer
   x = 882.95