Finding the Fourth Proportional to 2,609.92, 3,915.42 and 878.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,609.92 : 3,915.42 = 878.50 : x
2. Step 2: Convert to fraction form
   2,609.92/3,915.42 = 878.50/x
3. Step 3: Cross multiply
   2,609.92x = 3,915.42 × 878.50
4. Step 4: Simplify right side
   2,609.92x = 3,439,696.47
5. Step 5: Solve for x
   x = 3,439,696.47/2,609.92
6. Step 6: Final answer
   x = 1,317.93