Finding the Fourth Proportional to 1,105.58, 1,526.02 and 639.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.58 : 1,526.02 = 639.92 : x
2. Step 2: Convert to fraction form
   1,105.58/1,526.02 = 639.92/x
3. Step 3: Cross multiply
   1,105.58x = 1,526.02 × 639.92
4. Step 4: Simplify right side
   1,105.58x = 976,530.72
5. Step 5: Solve for x
   x = 976,530.72/1,105.58
6. Step 6: Final answer
   x = 883.27