Finding the Fourth Proportional to 2,640.16, 3,961.61 and 1,915.71

Step by Step Solution

1. Step 1: Write the proportion equation
   2,640.16 : 3,961.61 = 1,915.71 : x
2. Step 2: Convert to fraction form
   2,640.16/3,961.61 = 1,915.71/x
3. Step 3: Cross multiply
   2,640.16x = 3,961.61 × 1,915.71
4. Step 4: Simplify right side
   2,640.16x = 7,589,300.68
5. Step 5: Solve for x
   x = 7,589,300.68/2,640.16
6. Step 6: Final answer
   x = 2,874.56