Finding the Fourth Proportional to 1,388.63, 1,916.31 and 799.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.63 : 1,916.31 = 799.16 : x
2. Step 2: Convert to fraction form
   1,388.63/1,916.31 = 799.16/x
3. Step 3: Cross multiply
   1,388.63x = 1,916.31 × 799.16
4. Step 4: Simplify right side
   1,388.63x = 1,531,428.72
5. Step 5: Solve for x
   x = 1,531,428.72/1,388.63
6. Step 6: Final answer
   x = 1,102.84