Finding the Fourth Proportional to 1,104.78, 1,524.50 and 638.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,104.78 : 1,524.50 = 638.94 : x
2. Step 2: Convert to fraction form
   1,104.78/1,524.50 = 638.94/x
3. Step 3: Cross multiply
   1,104.78x = 1,524.50 × 638.94
4. Step 4: Simplify right side
   1,104.78x = 974,064.03
5. Step 5: Solve for x
   x = 974,064.03/1,104.78
6. Step 6: Final answer
   x = 881.68