Finding the Fourth Proportional to 2,603.98, 3,906.38 and 872.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,603.98 : 3,906.38 = 872.20 : x
2. Step 2: Convert to fraction form
   2,603.98/3,906.38 = 872.20/x
3. Step 3: Cross multiply
   2,603.98x = 3,906.38 × 872.20
4. Step 4: Simplify right side
   2,603.98x = 3,407,157.39
5. Step 5: Solve for x
   x = 3,407,157.39/2,603.98
6. Step 6: Final answer
   x = 1,308.44