Finding the Fourth Proportional to 1,388.28, 1,916.15 and 799.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.28 : 1,916.15 = 799.15 : x
2. Step 2: Convert to fraction form
   1,388.28/1,916.15 = 799.15/x
3. Step 3: Cross multiply
   1,388.28x = 1,916.15 × 799.15
4. Step 4: Simplify right side
   1,388.28x = 1,531,291.27
5. Step 5: Solve for x
   x = 1,531,291.27/1,388.28
6. Step 6: Final answer
   x = 1,103.01