Finding the Fourth Proportional to 1,915.31, 2,640.13 and 1,601.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,915.31 : 2,640.13 = 1,601.61 : x
2. Step 2: Convert to fraction form
   1,915.31/2,640.13 = 1,601.61/x
3. Step 3: Cross multiply
   1,915.31x = 2,640.13 × 1,601.61
4. Step 4: Simplify right side
   1,915.31x = 4,228,458.61
5. Step 5: Solve for x
   x = 4,228,458.61/1,915.31
6. Step 6: Final answer
   x = 2,207.71