Finding the Fourth Proportional to 2,105.45, 3,155.87 and 872.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.45 : 3,155.87 = 872.20 : x
2. Step 2: Convert to fraction form
   2,105.45/3,155.87 = 872.20/x
3. Step 3: Cross multiply
   2,105.45x = 3,155.87 × 872.20
4. Step 4: Simplify right side
   2,105.45x = 2,752,549.81
5. Step 5: Solve for x
   x = 2,752,549.81/2,105.45
6. Step 6: Final answer
   x = 1,307.35