Finding the Fourth Proportional to 1,104.56, 1,524.20 and 638.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,104.56 : 1,524.20 = 638.72 : x
2. Step 2: Convert to fraction form
   1,104.56/1,524.20 = 638.72/x
3. Step 3: Cross multiply
   1,104.56x = 1,524.20 × 638.72
4. Step 4: Simplify right side
   1,104.56x = 973,537.02
5. Step 5: Solve for x
   x = 973,537.02/1,104.56
6. Step 6: Final answer
   x = 881.38