Finding the Fourth Proportional to 1,105.82, 1,526.55 and 639.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.82 : 1,526.55 = 639.98 : x
2. Step 2: Convert to fraction form
   1,105.82/1,526.55 = 639.98/x
3. Step 3: Cross multiply
   1,105.82x = 1,526.55 × 639.98
4. Step 4: Simplify right side
   1,105.82x = 976,961.47
5. Step 5: Solve for x
   x = 976,961.47/1,105.82
6. Step 6: Final answer
   x = 883.47