Finding the Fourth Proportional to 1,388.68, 1,916.61 and 799.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.68 : 1,916.61 = 799.09 : x
2. Step 2: Convert to fraction form
   1,388.68/1,916.61 = 799.09/x
3. Step 3: Cross multiply
   1,388.68x = 1,916.61 × 799.09
4. Step 4: Simplify right side
   1,388.68x = 1,531,536.10
5. Step 5: Solve for x
   x = 1,531,536.10/1,388.68
6. Step 6: Final answer
   x = 1,102.87