Finding the Fourth Proportional to 2,640.70, 3,959.72 and 885.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,640.70 : 3,959.72 = 885.10 : x
2. Step 2: Convert to fraction form
   2,640.70/3,959.72 = 885.10/x
3. Step 3: Cross multiply
   2,640.70x = 3,959.72 × 885.10
4. Step 4: Simplify right side
   2,640.70x = 3,504,748.17
5. Step 5: Solve for x
   x = 3,504,748.17/2,640.70
6. Step 6: Final answer
   x = 1,327.20