Finding the Fourth Proportional to 1,388.09, 1,912.92 and 994.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.09 : 1,912.92 = 994.43 : x
2. Step 2: Convert to fraction form
   1,388.09/1,912.92 = 994.43/x
3. Step 3: Cross multiply
   1,388.09x = 1,912.92 × 994.43
4. Step 4: Simplify right side
   1,388.09x = 1,902,255.47
5. Step 5: Solve for x
   x = 1,902,255.47/1,388.09
6. Step 6: Final answer
   x = 1,370.42