Finding the Fourth Proportional to 2,200.70, 3,300.20 and 640.18

Step by Step Solution

1. Step 1: Write the proportion equation
   2,200.70 : 3,300.20 = 640.18 : x
2. Step 2: Convert to fraction form
   2,200.70/3,300.20 = 640.18/x
3. Step 3: Cross multiply
   2,200.70x = 3,300.20 × 640.18
4. Step 4: Simplify right side
   2,200.70x = 2,112,722.04
5. Step 5: Solve for x
   x = 2,112,722.04/2,200.70
6. Step 6: Final answer
   x = 960.02