Finding the Fourth Proportional to 2,391.70, 3,581.78 and 2,118.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,391.70 : 3,581.78 = 2,118.10 : x
2. Step 2: Convert to fraction form
   2,391.70/3,581.78 = 2,118.10/x
3. Step 3: Cross multiply
   2,391.70x = 3,581.78 × 2,118.10
4. Step 4: Simplify right side
   2,391.70x = 7,586,568.22
5. Step 5: Solve for x
   x = 7,586,568.22/2,391.70
6. Step 6: Final answer
   x = 3,172.04